WO2013053125A1

WO2013053125A1 - Method for transmitting unused frequency band information in a mobile communication system

Info

Publication number: WO2013053125A1
Application number: PCT/CN2011/080752
Authority: WO
Inventors: Wei Hong; Haiming Wang; Na WEI; Erlin Zeng
Original assignee: Renesas Mobile Corporation
Priority date: 2011-10-13
Filing date: 2011-10-13
Publication date: 2013-04-18

Abstract

The invention concerns a method, and a base station and an apparatus implementing the method. In the method a geographic location of a base station is provided to a database from which first information on at least one channel is received, the first information is transmitted in a first system information message to at least one mobile node. The elapsing of a predefined time is determined after which second information on at least one channel is obtained from the database. If the first information and second information do not match, a paging of at least one mobile node is performed. The paging indicates modified system information. A change of system information modification period is detected, after which the second information is transmitted in a second system information message.

Description

METHOD FOR TRANSMITTING UNUSED FREQUENCY BAND INFORMATION IN A MOBILE COMMUNICATION SYSTEM

BACKGROUND OF THE INVENTION

Field of the invention:

The invention relates to mobile communications networks, the deployment of new frequency bands and a method for transmitting unused frequency band information in a mobile communication system.

Description of the Related Art:

The field of data communications has been in turmoil during the recent years. New technologies are being introduced while old technologies are being dis- mantled. Particularly, the data rates in wireless mobile communication systems have been increasing in the recent years rapidly. Long-Term Evolution (LTE) standardized by the 3G Partnership Project (3GPP) represents a significant leap forward in wireless mobile communication systems. One of the main objectives of the LTE is the providing of downlink data rates of at least 150 Mbps and uplink date rates of at least 75 Mb s. The downlink data rate is based on 2x2 Multiple Input Multiple Output (MIMO) and 20 MHz band. The LTE operates in two modes, namely the Frequency Division Duplex ( FDD} and the Time Division Duplex (TDD) . In FDD the uplink and downlink transmissions use different frequency bands, which are separated by a frequency offset. Thus, the FDD operates in paired fre- quency bands. From a mobile node, that is, user equipment perspective there are two carrier frequencies one for the uplink transmission and another for the downlink reception. The downlink reception and uplink transmission occur simultaneously. The downlink recep- tion uses the Orthogonal Frequency Division Multiple Access (OFDMA) while the uplink transmission uses the Single Carrier Frequency Division Multiple Access (SC- FDMA) . The reason for the use of SC-FDMA in uplink transmission is the high Peak-to-Average Power Ratio (PAPR) in OFDMA signal transmission. An amplifier in an OFDMA transmitter must stay in amplifier linear area by using extra power back-off. This leads to increased battery consumption or shorter uplink range. The shorter uplink range may be a problem for mobile nodes that are far from a base station. In FDD the problem is the required availability of enough radio spectrum for the paired band. Therefore, TDD has been standardized as an alternative for FDD. TDD uses the same frequency band for transmission and reception so that the base station and the mobile node take turns in transmission. TDD emulates full-duplex transmission in a transmission which is essentially half-duplex in nature. This is possible because of the rapid change in the transmission direction. TDD offers seven configurations for uplink and downlink transmission alternation. The configurations comprise downlink intensive, uplink intensive or balanced transmission schemes. The number of subframes allocated for uplink and downlink vary in the configurations. Some of the frequency bands may not be wide enough for practical FDD transmission and TDD may be used instead within these frequency bands .

Frequency bands previously allocated for television channels are being opened for other uses. This is at least partly due to the dismantling of analog television broadcasting systems in many countries. Unused television channels or channel sets may be referred to as Television White Spaces (TVWS) TVWS. TVWS are located in the 54 - 698 MHz spectrum. For example, in USA the Federal Communications Commission (FCC) has decided to open spectrum traditionally allocated for television broadcast to provide wireless broadband access. One possible use for the spectrum opened is LTE transmission. The highly favorable propagation characteristics of the aforementioned spectrum allow for wireless broadband deployment with greater range of operation. The characteristics comprise the capability to pass through buildings, rain and foliage at lower power levels. Therefore, TVWS could be used to provide ubiquitous coverage for municipal wireless networks. For example, TDD may be used on the spectrum due to coordination issues or due to possible discontinuity or narrowness in the television channels available. Naturally, FDD may be used where sufficient bandwidth is available to support an uplink band, a downlink band and a gap between them.

A property of the TVWS is that on the TV channels immediately adjacent in the frequency domain to an active TV channel there are limits for transmission power in order to avoid band energy leakage to the active TV channel and resulting interference. Therefore, there are problems if downlink transmission from a base station to a mobile node must be performed in the frequency band of a TV channel that is immediately adjacent to a TV channel in active use. The high power in the downlink transmission is likely to cause interference in TV set receivers located within the coverage area of the base station. The downlink transmission power from the base station must be limited, which reduces the cell size. Similar considerations are present in the cases where bands near in the frequency domain to a band used for other purposes are available for LTE use and could thus be used for base station downlink transmission.

Several types and modes of Television Band Devices (TVBDs) have been defined by the FCC based on their characteristics. A fixed TVBD transmits and re^¬ ceives radio communication signals at a specified fixed location. A fixed TVBD must access a bands database. There are mode I and mode II portable, that is, personal devices. A sensing only device is a portable TVBD that uses spectrum sensing to determine a list of available channels. It may use the frequency bands 512-608 MHz (TV channels 21-36) and 614-698 MHz (TV channels 38-51) . Spectrum sensing is only defined for portable TVBDs . A fixed TVBD may operate as part of a communication system so that it transmits to at least one other fixed TVBD or to at least one personal portable TVBD. A mode I portable device does not use an internal geo-location positioning capability and accesses a TV bands database. It must obtain a channel list from either a fixed TVBD or Mode II portable TVBD The FCC identifier of the mode I portable device must be verified by the fixed TVBD or Mode II portable TVBD The list of channels provided to a Mode I device must be the same as the list of channels that are available to the fixed or Mode II device. To initiate a contact with a fixed TVDB or a Mode II device, a Mode I device may transmit on an available channel used by the fixed or Mode II TVBD or on a channel the fixed or Mode II TVBD indicates is available for use by a Mode I device on a signal seeking such contacts. At least once every 60 seconds, except when in sleep mode, that is, in a mode in which the device is inactive but is not pow- ered-down, a Mode I device must either receive a contact verification signal from the Mode II or fixed device that provided its current list of available channels or contact a Mode II or fixed device to re-verify or re-establish channel availability. A Mode I device must cease operation immediately, if it does not receive a contact verification signal or is not able to re-establish a list of available channels through contact with a fixed or Mode II device on this schedule. A mode II portable device comprises similar functions as a fixed TVBD, but it does not need to transmit or receive signals at a specified and fixed geographic position. A particular concern is that associated with the different types and modes of TVDBs there are dif^¬ ferent transmission power upper limits. For a fixed TVBD, the maximum power delivered to a Transmission (TX) antenna must not exceed 1W. For portable TVBDs, the maximum Effective Isotropic Radiated Power (EIRP) is lOOmW (20dBm) . If a portable TVBD does not meet the adjacent channel separation requirements, which means that the distance between the TVBD and the TV station is smaller than the minimum distance requirement, the maximum EIRP is 40mW (16dBm) . The maximum power spectral densities, for any 100 kHz during any time interval of continuous transmission, for different types of TVBDs are: fixed devices 12.2dBm, portable devices operating adjacent to occupied TV channels -1.6dBm and a sensing only device -0.8dBm. For all other portable devices the maximum power spectral density 2.2dBm.

It would be beneficial to be able to use TV channels in a mobile communication system. One particular such use is for device-to-device communication There must be an efficient method for distributing information on the available channels to mobile terminals of a mobile communication system. The distribution should be rapid and should not consume too much radio resources. The specific enquiring of TVWS available channels by a mobile terminal has certain problems such as the consumption of radio resources and the consumption of mobile terminal battery. Recall that the available channels must be re-enquired or re- verified at least once in 60 seconds, which would require many random accesses and signaling radio bearer establishments without involving any useful traffic for the user or the operator. Before a mobile terminal may transmit on TVWS it must receive the available channel information. However, this may be a prerequisite for receiving information from the fixed TVBD in the first place, if other bands or fixed connections are not used. SUMMARY OF THE INVENTION :

According to an aspect of the invention, the invention is a method, comprising: determining a geographic location of a base station; providing the geographic location to a frequency bands database; receiving first information on at least one channel from the frequency bands database; forming a first channel list using the first information, the first channel list comprising at least one channel entry, the channel entry comprising information on a channel; transmitting the first channel list in a first system information message to at least one mobile node; determining the elapsing of a predefined time; obtaining second information on at least one channel from the frequency bands database, in response to the elapsing of the predefined time; comparing the first information to the second information; paging the at least one mobile node in response to the comparison revealing changed information in the second information in relation to the first information, the paging indicating modified system information; forming a second channel list using the second information, the second channel list comprising at least one channel entry, the channel entry comprising information on a channel; and transmitting the second channel list in a second system information message to the at least one mobile node .

According further aspect the mven- tion, the invention is a method, comprising: receiving a first channel list in a first system information message from a base station in a mobile node; extracting the first channel list from the first system information message; transmitting, from the mobile node, at least one signal to a remote node using at least one radio resource comprised in at least one channel indicated as vacant in the first channel list; receiv- ing a paging from the base station, the paging indicating modified system information; receiving a second channel list in a second system information message from the base station; determining whether there is ongoing or scheduled transmission from the mobile node using the at least one radio resource comprised in the at least one channel indicated as vacant in the first channel list and indicated as no longer vacant in the second channel list; and stopping the transmission in case there is ongoing or scheduled transmission from the mobile node using the at least one radio resource comprised in the at least one channel indicated as vacant in the first channel list and indicated as no longer vacant in the second channel list.

According to a further aspect of the invention, the invention is a base station comprising: at least one transmitter configured to transmit a first system information message and a second system information message; and at least one processor configured to determine a geographic location of the base station, to provide the geographic location to a frequency bands database, to receive first information on at least one channel from the frequency bands database, to form a first channel list using the first information, the first channel list comprising at least one channel entry, the channel entry comprising information on a channel, to transmit the first channel list in the first system information message to at least one mobile node, to determine the elapsing of a predefined time, to obtain second information on at least one channel from the frequency bands database, in response to the elapsing of the predefined time, to compare the first information to the second information, to page the at least one mobile node in response to the comparison revealing changed information in the second information in relation to the first information, the paging indicating modified system informa- tion, to form a second channel list using the second information, the second channel list comprising at least one channel entry, the channel entry comprising information on a channel, and to transmit the second channel list in the second system information message to the at least one mobile node.

According to a further aspect of the invention, the invention is an apparatus comprising: at least one processor configured to receive a first channel list in a first system information message from a base station in the apparatus, to extract the first channel list from the first system information message, to transmit, from the apparatus, at least one signal to a remote node using at least one radio resource comprised in at least one channel indicated as vacant in the first channel list, to receive a paging from the base station, the paging indicating modified system information, to receive a second channel list in a second system information message from the base station, to determine whether there is ongoing or scheduled transmission from the mobile node using the at least one radio resource comprised in the at least one channel indicated as vacant in the first channel list and indicated as no longer vacant in the second channel list, and to stop the transmission in case there is ongoing or scheduled transmission from the mobile node using the at least one radio resource comprised in the at least one channel indicated as vacant in the first channel list and indicated as no longer vacant in the second channel list.

In one embodiment of the invention, the apparatus comprises a receiver configured to receive the first system information message and the second system information message.

In one embodiment of the invention, the apparatus comprises a mobile node, for example, a User Equipment (UE) . According to a further aspect of the invention, the invention is a base station comprising: means for determining a geographic location of a base station; means for providing the geographic location to a frequency bands database; means for receiving first information on at least one channel from the frequency bands database; means for forming a first channel list using the first information, the first channel list comprising at least one channel entry, the channel entry comprising information on a channel; means for transmitting the first channel list in a first system information message to at least one mobile node; means for determining the elapsing of a predefined time; means for obtaining second informa^¬ tion on at least one channel from the frequency bands database, in response to the elapsing of the predefined time; means for comparing the first information to the second information; means for paging the at least one mobile node in response to the comparison revealing changed information in the second information in relation to the first information, the paging indicating modified system information; means for forming a second channel list using the second information, the second channel list comprising at least one channel entry, the channel entry comprising information on a channel; and means for transmitting the second channel list in a second system information message to the at least one mobile node.

According to a further aspect of the invention, the invention is an apparatus comprising: means for receiving a first channel list in a first system information message from a base station in a mobile node; means for extracting the first channel list from the first system information message; means for transmitting, from the mobile node, at least one signal to a remote node using at least one radio resource comprised in at least one channel indicated as vacant in the first channel list; means for receiving a paging from the base station, the paging indicating modified system information; means for receiving a second channel list in a second system information message from the base station; means for determining whether there is ongoing or scheduled transmission from the mobile node using the at least one radio resource comprised in the at least one channel indicated as vacant in the first channel list and indicated as no longer vacant in the second channel list; and means for stopping the transmission in case there is ongoing or scheduled transmission from the mobile node using the at least one radio resource comprised in the at least one channel indicated as vacant in the first channel list and indicated as no longer vacant in the second channel list .

According to a further aspect of the invention, the invention is a computer program comprising code adapted to cause the following when executed on a data-processing system: determining a geographic location of a base station; providing the geographic location to a frequency bands database; receiving first information on at least one channel from the frequency bands database; forming a first channel list using the first information, the first channel list comprising at least one channel entry, the channel entry comprising information on a channel; transmitting the first channel list in a first system information message to at least one mobile node; determining the elapsing of a predefined time; obtaining second information on at least one channel from the frequency bands database, in response to the elapsing of the predefined time; comparing the first information to the second information; paging the at least one mobile node in response to the comparison revealing changed information in the second information in relation to the first information, the paging indicating modified system informa- tion; forming a second channel list using the second information, the second channel list comprising at least one channel entry, the channel entry comprising information on a channel; and transmitting the second channel list in a second system information message to the at least one mobile node.

According to a further aspect of the invention, the invention is a computer program product comprising the computer program.

According to a further aspect of the invention, the invention is a computer program comprising code adapted to cause the following 'when executed on a data-processing system: receiving a first channel list in a first system information message from a base station in a mobile node; extracting the first channel list from the first system information message; transmitting, from the mobile node, at least one signal to a remote node using at least one radio resource comprised in at least one channel indicated as vacant in the first channel list; receiving a paging from the base station, the paging indicating modified system information; receiving a second channel list in a second system information message from the base station; determining whether there is ongoing or scheduled transmission from the mobile node using the at least one radio resource comprised in the at least one channel indicated as vacant in the first channel list and indicated as no longer vacant in the second channel list; and stopping the transmission in case there is ongoing or scheduled transmission from the mobile node using the at least one radio resource comprised in the at least one channel indicated as vacant in the first channel list and indicated as no longer vacant in the second channel list.

According to a further aspect of the invention, the invention is a computer program product com^¬ prising the computer program. According to a further aspect of the invention, the invention is system comprising the apparatus and the base station.

According to a further aspect of the inven- tion, the invention is a method, comprising: providing the geographic location of a base station or an identity of a base station to a database; receiving first information on at least one channel from the database; forming a first channel list using the first informa- tion, the first channel list comprising at least one channel entry, the channel entry comprising information on a channel; transmitting the first channel list in a first system information message to at least one mobile node; obtaining second information on at least one channel from the database; forming a second channel list using the second information, the second channel list comprising at least one channel entry, the channel entry comprising information on a channel; and transmitting the second channel list in a second system information message to the at least one mobile node .

According to further aspect of the invention, the invention is a method. In the method a geographic location of a base station is provided to a database from which first information on at least one channel is received, the first information is transmitted in a first system information message to at least one mobile node. The elapsing of a predefined time is determined after which second information on at least one channel is obtained from the database. If the first information and second information do not match, a paging of at least one mobile node is performed. The paging indicates modified system information. A change of system information modification period is detected, after which the second information is transmitted in a second system information message. According to a further aspect of the invention, the invention is an apparatus comprising: at least one processor configured to determine a geographic location of a base station, to provide the geographic location to a frequency bands database, to receive first information on at least one channel from the frequency bands database, to form a first channel list using the first in-formation, the first channel list comprising at least one channel entry, the channel entry comprising information on a channel, to transmit the first channel list in the first system information message to at least one mobile node, to determine the elapsing of a predefined time, to obtain second information on at least one channel from the frequency bands database, in response to the elapsing of the predefined time, to compare the first information to the second information, to page the at least one mobile node in response to the comparison revealing changed information in the second information in relation to the first information, the paging indicating modified system information, to form a second channel list using the second information, the second channel list comprising at least one channel entry, the channel entry comprising information on a channel, and to transmit the second channel list in the second system information message to the at least one mobile node .

In one embodiment of the invention, the apparatus comprises a base station server.

In one embodiment of the invention, the apparatus comprises a base station. The apparatus may have associated with it at least one transmitter. The apparatus may have associated with it at least one receiver .

In one embodiment of the invention, the apparatus comprises a chip or a chipset. In one embodiment of the invention, the base station comprises at least one radio frequency circuit Each of the at least one transmitter may comprise at least one radio frequency circuit. Each of the at least one transmitter may also comprise a receiver. Alternatively, at least one of the at least one transmitter may also comprise, or be communicatively connected to, a receiver of the base station.

In one embodiment of the invention, a change of a system information modification period is determined by the at least one processor of the base station, before the second channel list is transmitted in the second system information message to the at least one mobile node. The system information modification period may also be referred to as a modification period. System information regarding a base station may change at a modification period boundary. In one embodiment of the invention, the system information in repeated system information messages, for example, the first system information message, does not change until the next modification period starts.

In one embodiment of the invention, the system information modification period may also be referred to as a modification period.

In one embodiment of the invention, the transmission of the first system information message may be repeated before the transmission of the second system information message. The repetition may be performed until a change of a system information modification period is determined.

In one embodiment of the invention, the predefined time is a period or a time cycle in which the base station must check the frequency bands database, for example, regarding the vacancy of a channel, for example, among the at least one channel on which information has been provided from the frequency bands database. The predefined time may be set to be smaller than or equal to the time in which a fixed TVBD or Mode II TVBD must contact a TV bands database to obtain updated information on the current status of the channels in the first channel list entries.

In one embodiment of the invention, the predefined time is a period in which the base station must perform spectrum sensing on at least one channel on which information has been provided from the frequency bands database.

In one embodiment of the invention, at least one of the system information modification period and the periodicity of the first system information message and the second system information message, is set to have a duration that is shorter than a time, in which transmission in a channel indicated as no longer vacant by the frequency band database for the base station or by spectrum sensing performed by the base station, must be stopped by the mobile node. The duration may be, for example, 2 seconds or less than 2 seconds .

In one embodiment of the invention, at least one of the system information modification period or the periodicity of the first system information message and the second system information message, is set to have a duration, which, when added to the periodicity of the enquiries of the frequency bands database by the base station, does not exceed a time set as a maximum periodicity for enquiring of a frequency bands database, for example, a TVWS database, by the mobile node or a Mode II device. For example, the duration may be, for example, less than 30 seconds, if the periodicity of the enquiries of the frequency bands database by the base station is 30 seconds and the maximum periodicity for enquiring of a frequency bands database, for example, a TVWS database, by the mobile node or a Mode II device is 60 seconds. In one embodiment of the invention, the at least one processor of the base station is further configured to transmit a third system information mes^¬ sage to at least one mobile node, the third system in^¬ formation message comprising information on the periodicity of the first system information message and the second system information message. The at least one transmitter may be configured to transmit the third system information message.

In one embodiment of the invention, the at least one processor of the base station is further configured to determine at least one target mobile node, which is transmitting or permitted to transmit, on the at least one channel, determine whether the number of mobile nodes is below a predefined threshold value, and transmit the first channel list as a dedicated signaling message to the at least one target mobile node. The at least one transmitter may be configured to transmit the dedicated signaling message, for example, on a physical uplink shared channel.

In one embodiment of the invention, the at least one processor of the base station is further configured to bypass the transmitting of the first system information message, the paging of the at least one mobile node, and transmitting of the second system information message, in case the first channel list is transmitted as a dedicated signaling message.

In one embodiment of the invention, the at least one processor of the base station is further configured to bypass the transmitting of the first channel list in the first system information message and bypassing the transmitting of the second channel list in the second system information message, in case the first channel list is transmitted as a dedicated signaling message. By bypassing the transmission of a channel list in a system information message is meant that the channel list is not added in the system in^¬ formation message.

In one embodiment of the invention, the at least one processor of the base station is further configured to determine load on each vacant channel of the first channel list, and to add information on the load to each channel entry in the first channel list. The at least one processor of the base station may be further configured to determine load on each vacant channel of the second channel list, and to add information on the load to each channel entry in the second channel list.

In one embodiment of the invention, the step of determining load on each vacant channel of the first channel list further comprises determining, for each vacant channel of the first channel list, the number of mobile nodes transmitting or permitted to transmit on the vacant channel of the first channel list. The information on the number of mobile nodes transmitting or permitted to transmit on a given vacant channel of the first channel list may be obtained by the at least one processor of the base station based on radio resource usage reports from the mobile node. A usage report may indicate that the mobile node has started to use at least one radio resource within at least one channel comprised in the channel entries of the first channel list. The use may apply semi- persistent scheduling. The at least one radio resource may be used periodically. A usage report may also in- dicate that the mobile node has stopped to use at least one radio resource within at least one channel comprised in the channel entries of the first channel list.

In one embodiment of the invention, the at least one transmitter is further configured to transmit the first system information message and the sec- ond system information message using orthogonal frequency division multiple access.

In one embodiment of the invention, the base station comprises a Long-Term Evolution (LTE) Evolved Node B.

In one embodiment of the invention, the frequency bands database is a television bands database and the at least one channel is a television channel.

In one embodiment of the invention, the at least one processor in the apparatus is configured to determine that the remote node is within a transmission range of the mobile node.

In one embodiment of the invention, the at least one processor in the apparatus is configured to transmit, from the mobile node, a first test signal to the remote node and to increase transmission power for a second test signal to the remote node, in the absence of a response from the remote node.

In one embodiment of the invention, the at least one processor in the apparatus is configured to request or indicate a reservation of the at least one radio resource. The at least one processor in the apparatus may also be configured to receive a confirmation or determine the success of the reservation of the at least one radio resource by receiving at least one signal indicating a reservation status of the at least one radio resource.

In one embodiment of the invention, the indication or request of the reservation is on a radio resource comprised in the at least one channel indicated as vacant in the first channel list or the second channel list.

In one embodiment of the invention, the confirmation of the reservation is determined by receiving a radio resource comprised in the at least one channel indicated as vacant in the first channel list. In one embodiment of the invention, the at least one processor of the apparatus is also configured to determine the success of the reservation of the at least one radio resource from the absence of a transmission from any other mobile node on a specific radio resource, which may be comprised in the at least one channel indicated as vacant in the first channel list or the second channel list.

In one embodiment of the invention, the at least one processor in the apparatus is configured to request a reservation of the at least one radio resource. The request may also be called a claiming or an indication of the reservation. The request may not require an explicit confirmation signal from any remote transmitter. The reservation may be requested using a radio resource comprised in the at least one channel indicated as vacant in the first channel list. The at least one processor of the apparatus may be configured to first check .that the radio resource used for the request does not have a signal indicating an existing request for reservation.

In one embodiment of the invention, the at least one processor of the apparatus is configured to detect a success of the reservation of the at least one radio resource. The success may be detected by determining an absence of transmission on a specific radio resource, which may be comprised in the at least one channel indicated as vacant in the first channel list or the second channel list. The specific radio resource may be at least one specific resource element The at least one specific resource element may have specific repetition timing.

In one embodiment of the invention, the detecting of the success of the reservation is performed by receiving a confirmation on a radio resource comprised in the at least one channel indicated as va- cant in the first channel list. The confirmation may be received from the base station.

In one embodiment of the invention, the second information from the frequency band database may comprise information on new channels or on removed channels in relation to the first information.

In one embodiment of the invention, the first and the second information may be organized as a list of channels with information on each channel on the list .

In one embodiment of the invention, the sec^¬ ond information from the frequency band database may indicate changes in channel vacancy in relation to the first information.

In one embodiment of the invention, the radio resource comprises at least one resource element, the resource element comprising at least one subcarrier within the period of at least one Orthogonal Frequency Division Multiple Access (OFDMA) or Single-Carrier Frequency Division Multiple Access (SC-FDMA) symbol. The period may comprise a cyclic prefix.

In one embodiment of the invention, the radio resource may comprise a number of temporally separate resource elements. The radio resource may be at least one semi-permanently allocated resource, which may be at least one resource element or at least one resource block.

In one embodiment of the invention, the radio resource comprises at least one resource element, for example, an LTE resource element. The resource elements may be seen as elements in a resource grid. The resource element may be within a Television White Spaces (TVWS) frequency band.

In one embodiment of the invention, the radio resource comprises at least one resource block, for example, an LTE resource block. The resource block may be in a Television White Spaces (TVWS) frequency band. In one embodiment of the invention, the radio resource may comprise at least one of a channel, a frequency range, a subcarrier, a frequency range within a specific time period that may be repeated at specific intervals, a subcarrier within a specific time period that may be repeated at specific intervals, a carrier within a specific time period that may be repeated at specific intervals, and a slot, for example, a timeslot.

In one embodiment of the invention, the at least one radio resource may be comprised in the frequency range of at least two channels, for example, television channels.

In one embodiment of the invention, a channel is referred to as a sub-band or a frequency range.

In one embodiment of the invention, at least one synchronization signal comprises at least one downlink symbol on at least one subcarrier.

In one embodiment of the invention, determining timing based on the at least one synchronization signal from the base station comprises determining at least one of a slot boundary, a subframe boundary, a frame boundary and a symbol boundary in time domain.

In one embodiment of the invention, the at least one synchronization signal comprises a group of orthogonal frequency division multiple access resource elements which may be on adjacent subcarriers or on adjacent symbols.

In one embodiment of the invention, the at least one processor of the mobile node is further configured to receive from the base station a request to stop using the at least one radio resource at the mobile node.

In one embodiment of the invention, the mobile node comprises a Long-Term Evolution (LTE) User Equipment . In one embodiment of the invention, the re^¬ mote node is a remote mobile node, for example an LTE User Equipment (UE) . The remote node may also be a desktop, a desk computer or a server.

In one embodiment of the invention, the method comprises determining that the remote node is within a transmission range of the mobile node. This may be executed by at least one of the at least one radio frequency circuit and the at least one processor of the base station.

In one embodiment of the invention, the step of determining that the remote node is within a transmission range of the mobile node further comprises transmitting from the base station a request to exe- cute the transmission of at least one test signal between the mobile node and the remote node; and receiving a report of a quality of reception of the at least one test signal to the base station.

In one embodiment of the invention, the de- termination that the remote node is within a transmission range of the mobile node uses at least one of a satellite positioning system, a geographic positioning system of a mobile communication system, and a determination of a sector of the mobile node and the remote mobile node.

In one embodiment of the invention, the symbols are OFDMA or Single Carrier Frequency Division Multiple Access (SC-FDMA) symbols.

In one embodiment of the invention, the mo- bile node comprises a Long-Term Evolution (LTE) User Equipment. At least one processor in the mobile node may be configured to perform the method steps disclosed hereinabove. The transmission, reception and timing related method steps may be performed by at least one radio frequency circuit.

In one embodiment of the invention, the base station is an apparatus comprising a number of base station receivers and/or transmitters and a base station node. The base station node may be a base station server or a central unit.

In one embodiment of the invention, the at least one radio frequency circuit of the base station is comprised in the at least one a base station trans^¬ mitter and/or receiver and the at least one processor of the base station is comprised in a base station node. In one embodiment of the invention, the at least one transmitter of the base station may also comprise at least one receiver.

In one embodiment of the invention, the at least one processor of the base station may be comprised in a base station server. The at least one transmitter of the base station may be remotely located, for example, in association with an antenna.

In one embodiment of the invention, the base station comprises an Evolved UMTS Radio Access Network (E-UTRAN) node such as, for example, an Evolved NodeB. At least one processor in the base station node may be configured to perform the method steps disclosed hereinabove. The transmission and reception may be performed by the at least one radio frequency circuit.

In one embodiment of the invention, the first system information message and the second system information message are transmitted within a frequency range comprised in at least one channel indicated as vacant in at least one of the first information and the second information from the frequency band database .

In one embodiment of the invention, the base station comprising a channel detection processor configured to determine channels of a television radio band which are free of signal transmission and channels with active signal transmission. The base station may also comprise a channel or frequency band database or a communication interface to remote database for such purpose from which channel availability may be determined, for example, using the location of the base station.

In one embodiment of the invention, the base station comprises an OFDMA radio network node or an SC-FDMA radio network node.

In one embodiment of the invention, at least one Radio Frequency (RF) circuit in the mobile node may also be referred to as at least one circuit.

In one embodiment of the invention, at least one Radio Frequency (RF) circuit in the base station node may also be referred to as at least one circuit.

In one embodiment of the invention, the mobile node such as a User Equipment (US) comprises a mobile station or generally a mobile terminal. In one embodiment of the invention a user of a mobile terminal is identified using a subscriber module, for example, User Services Identity Module (USIM) or a Subscriber Identity Module (SIM) . The combination of Mobile Equipment (ME) and a subscriber module may be referred to as a mobile subscriber. A mobile subscriber may be identified using an IMSI. In one embodiment of the invention to the User Equipment may be connected or inserted a Universal Integrated Circuit Card (UICC) . The UICC is the physical card with basic logical functionality and USIM is an application on a UICC. The UICC can contain multiple applications like the SIM (for GSM), USIM and ISIM (for IMS). The UICC may also be called a UMTS IC Card (UICC) .

In one embodiment of the invention, the apparatus is a mobile terminal, for example a, mobile handset .

In one embodiment of the invention, the apparatus is a semiconductor circuit, a chip or a chipset.

In one embodiment of the invention, the base station node is configured to be used in a 4G system such as, for example, LTE E-UTRAN . In one embodiment of the invention, the computer program is stored on a computer readable medium. The computer readable medium may be, but is not lim^¬ ited to, a removable memory card, a removable memory module, a magnetic disk, an optical disk, a holographic memory or a magnetic tape. A removable memory module may be, for example, a USB memory stick, a PCMCIA card or a smart memory card.

The embodiments of the invention described hereinbefore may be used in any combination with each other. Several of the embodiments may be combined together to form a further embodiment of the invention. A method, a base station, an apparatus, a computer program, a computer program product or system to which the invention is related may comprise at least one of the embodiments of the invention described hereinbefore .

It is to be understood that any of the above embodiments or modifications can be applied singly or in combination to the respective aspects to which they refer, unless they are explicitly stated as excluding alternatives .

The benefits of the invention are related to the reduced use of radio resources in a mobile commu- nication system pertaining to the transmitting of information on used and unused frequency bands to mobile nodes and to the timely reacting to changes regarding the status of those frequency bands. BRIEF DESCRIPTION OF THE DRAWINGS :

The accompanying drawings, which are included to provide a further understanding of the invention and constitute a part of this specification, illustrate embodiments of the invention and together with the description help to explain the principles of the invention. In the drawings: Fig. 1 illustrates two cells and a mobile node within a mobile communication system in one embodiment of the invention;

Fig. 2 is a message sequence chart illustrating the transmission of unused frequency band information in a mobile communication system in one embodiment of the invention;

Fig. 3 is a flow chart illustrating a method for transmitting information on unused and used frequency bands from a base station in one embodiment of the invention;

Fig. 4 is a flow chart illustrating a method for receiving information on unused and used frequency bands to a mobile node in one embodiment of the invention ;

Fig. 5 illustrates an apparatus in one embodiment of the invention; and

Fig. 6 illustrates a base station in one embodiment of the invention.

DETAILED DESCRIPTION OF THE EMBOD MEN S:

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

Figure 1 illustrates two cells and a mobile node within a mobile communication system in one embodiment of the invention. In Figure 1 is shown a radio access network 100 in a mobile communication system. The radio access network 100 comprises a base station 110 and a base station 120. The coverage areas of base stations 110 and 120 are illustrated with sectors 112 and 122, respectively. The base stations are communicatively connected to a frequency bands database 130, which may also be called for simplicity a database 130. Base station 110 and base station 120 may communicate with database 130 via a network, for example, an IP network, for example, the Internet. Database 130 stores information on at least one sub-band, for example, sub-band 154 on at least one frequency band 152. The at least one frequency band may be dif- ferent from primary frequency bands 150 used by base station 110 and base station 120. Database 130 may be a Television White Spaces (TVWS) database, which stores information on at least one television channel, for example, a television channel 154. Database 130 may store information on the current status of the at least one sub-band among the at least one sub-band. The current status may comprise information on the vacancy of the sub-band or presence of transmission on the sub-band. The signal levels or general availabil- ity of sub-bands, for example, television channels may differ depending on a geographic region. In Figure 1 there is illustrated with line 132 that base station 110 and base station 120 belong to different geographic regions as to the signal levels or general availability of sub-bands.

In Figure 1 there is illustrated a mobile node 102 which communicates with base station 110 as illustrated with arrow 140. Base station 110 communicates periodically with database 130, as illustrated with arrow 142. Base station 110 is configured to obtain periodically information on the at least one sub- band among the at least one frequency band 152. The period may be, for example, 5 seconds to 60 seconds. Base station 110 is configured to broadcast periodi- cally the information on the at least one sub-band among the at least one frequency band 152 to each mobile station in a cell footprint of base station 110, for example, sector 112. The broadcasting may be performed in association with the broadcasting of system configuration information. In response to receiving the information on the at least one sub-band among the at least one frequency band 152, mobile node 102 may obtain information on a vacant sub-band, for example, sub-band 154. In Figure 1 there is illustrated that at time Tl mobile node 102 moves from cell footprint 122 to cell footprint 112, which is a result of the transmission from base station 110. When in cell footprint 112, mobile node 102 must receive broadcast information on at least one radio band supported by base station 110 for communication to/from mobile nodes in cell footprint 112. In one embodiment of the invention the at least one radio band supported by base station 110 comprises at least one of frequency band 150 and frequency band 152. In one embodiment of the invention frequency band 152 is for device-to-device communication between mobile nodes.

In one embodiment of the invention, mobile node 102 may select at least one radio resource comprised in the vacant sub-band for transmission to a remote node. The remote node may be a fixed node, for example, base station 110, or a mobile node 104. In one embodiment of the invention, the selection may be indicated by mobile node 102 to other devices using a specific physical channel, which belongs to either frequency band 150 or frequency band 152. If there is no collision regarding the transmission of the indication and/or no other mobile node has selected at least one of the at least one radio resource and indicated this using the specific physical channel, mobile node 102 may transmit at least one signal using the at least one radio resource to mobile node 104, as illustrated with arrow 144. In one embodiment of the invention, the specific physical channel is transmitted using a power that is sufficient to reach mobile nodes that may be reached using the transmission of device- to-device communication user data signals.

In one embodiment of the invention, mobile node 102 may select at least one radio resource comprised in the vacant sub-band for transmission to a remote node. The remote node may be a fixed node, for example, base station 110 or a mobile node 104. Mobile node 102 may tune to the selected at least one radio resource comprised in the vacant sub-band and determine that the at least one radio resource does not have a signal exceeding a predefined power level. This may meant that mobile node 102 performs carrier sensing. Thereupon, mobile node 102 may start transmitting on the at least one radio resource selected.

In one embodiment of the invention, mobile node 102 may first transmit a test signal to mobile node 104 on using a lower power level. If there is no response from mobile node 104, mobile node 102 may repeat the transmission of the test signal to mobile node 104 using an increased power level. The transmission of the test signal may be repeated until a response from mobile node 104 is received or an upper limit for the power level is reached.

In one embodiment of the invention, mobile node 102 and mobile node 104 may obtain timing for their mutual device-to-device communication from at least the reception of a primary synchronization signal and a secondary synchronization signal from base station 110. Additionally, the timing may be made more accurate using information on at least the downlink delay between mobile node 102 and base station 110 or the downlink delay between mobile node 104 and base station 110.

In one embodiment of the invention, base station 110 determines a geographic location of base station 110, for example, using a satellite positioning system or from a memory of base station 110, in case base station 110 is not movable. Base station uses the geographic location to obtain information on at least one channel from database 130. Using the information on the at least one channel, base station 110 forms and sends a broadcast message comprising a channel list, which comprises at least one channel entry com^¬ prising information on a channel within frequency band 152. Upon the elapsing of a predefined period, base station 110 repeats the obtaining of information on at least one channel from database 130 using the geographic location. Base station 110 broadcasts the newly obtained information, at least if there is a difference in the information in relation to the previous time of obtaining the information from database 130. In one embodiment of the invention, base station 110 transmits at least one LTE physical channel format on the at least one channel obtained from database 130.

In one embodiment of the invention, base station 110 may be comprised in an LTE mobile communica- tion system, comprising, for example, an Evolved UMTS Radio Access Network (E-UTRAN) , Base station 110 in E- UTRAN parlance is called an Evolved Node B (eNB) . Base station 110 may comprise at least one Remote Radio Heads (RRH) (not shown) communicating with a base sta- tion server within base station 110. The mobile nodes 102 and 104 may also be referred to as User Equipments (UE) , mobile stations or mobile terminals. Mobile nodes 102 and 104 may be configured for device-to- device transmission. By device-to-device transmission is meant, for example, radio communication occurring directly between devices such as UEs, which may also receive downlink transmissions from a base station such as base station 110. In LTE an eNB, such as base station 160, performs radio resource management, com- prising radio bearer control, radio admission control, connection mobility control and dynamic allocation of resources to UEs such as mobile node 102 and mobile node 104.

It should be noted that the number of network elements in Figure 1 is just for illustrative purposes. There may be any number of network elements illustrated in Figure 1. The embodiments of the invention described hereinbefore in association with Figure 1 may be used in any combination with each other. Several of the em^¬ bodiments may be combined together to form a further embodiment of the invention.

Figure 2 is a message sequence chart illustrating the transmission of unused frequency band information in a mobile communication system in one embodiment of the invention.

In Figure 2 there is a mobile node 250, for example, an LTE UE. There is also a base station 254, for example, an E-UTRAN Evolved Node B (eNB) . There is also a remote node 252, for example, a remote mobile node, for example, an LTE UE . In one embodiment of the invention, the network elements in Figure 2 correspond to the respective network elements of Figure 1.

The starting point in Figure 2 is that mobile node 250 has moved to the area of a cell of base station 254 and has started listening to broadcast channels from base station 254. Mobile node 250 may also have been powered on in the area of a cell of base station 254. Mobile node 250 may first receive a primary synchronization signal and a secondary synchronization signal from base station 254 whereby mobile node 250 has knowledge of the frame boundaries. Mobile node 250 receives from base station 254 radio frames, the length of which may be 10 ms . The radio frames have a System Frame Number (SFN) . Within radio frames there are 1 ms subframes, which further comprise 0.5 ms slots. At time Tl, base station 254 transmits to mobile node 250 via a physical broadcast channel a master information block, as illustrated with arrow 201. The master information block may be provided in subframe 0. The first transmission of the master information block is scheduled in subframe 0 of radio frames for which SFN mod 4 = 0. The master information block is repeated in subframe 0 in each radio frame. At time T2, base station 254 transmits to mobile node 250 a System Information (SI) message comprising a System Information Block (SIB) type 1, which uses a fixed schedule with a periodicity of 80 ms . First transmission of system information block type 1 is scheduled in subframe 5 in radio frames having SFN mod 8 - 0. Repetitions may be scheduled in subframe 5 in radio frames having SFN mod 2 = 0. In Figure 1 it is assumed that SIB type 1 comprises scheduling information, for example, in a scheduling information list which indicates periodicity for different system in^¬ formation messages, for example, a system information message comprising a channel list, which comprises at least one channel entry. The channel entry comprises information on a channel, for example, on a television channel. The system information message comprising the channel list is herein illustrated to comprise a sys^¬ tem information block type 14. However, the type number may be any other unreserved type number. The periodicity for system information messages may be expressed in radio frames, for example, 8, 16 or 32 radio frames or, for example, in different exponents of 2 of radio frames. The system information messages also have a time window for their transmission. The time window may be expressed in milliseconds, that is, in subframes. The start of the time window for a system information message carrying a particular SIB type, that is, the first subframe in which a particular SIB type may be transmitted, is computed using, for example, the order of the particular SIB type in scheduling information list comprised in SIB type 1 and the time window for system information message transmission. At time T3 base station 254 transmits a system information message comprising SIB type 14 to mobile node 250, as illustrated with arrow 203. SIB type 14 comprises a first channel list. The time T3 occurs at the start of a subframe, named subframe! a, comprised within a radio frame of the periodicity of SI messages comprising SIB type 14 as indicated in scheduling information in the SIB type 1. The periodicity of SI messages comprising SIB type 14 is indicated as p in Figure 2. In response to receiving SI message illustrated with arrow 203, mobile node 250 starts a verification timer illustrated in Figure with abbreviation VT, which indicates a time in which mobile node 250 needs to start receiving SIB type 14 in an SI message or other message comprising a second channel list. Before time T4 base station 254 has obtained from a frequency band database, for example, a TV bands database, the second channel list. The second channel list may indicate modifications to the vacancy or status of at least one channel in the channel list.

In one embodiment of the invention, base station 254 may also perform scanning in the frequencies of the channels in the channel list to determine whether there is a transmission exceeding a predefined power level that indicates the presence of actual TV transmission on at least one channel. The scanning may also be called spectrum sensing. Base station 254 may perform at least one of signal time domain and frequency domain analysis of the transmission on the at least one channel to determine whether a signal received on at least one of the at least one channel corresponds to a TV signal. The TV signal may be analog or digital. In response, base station 254 may form the second channel list.

Further, before time T4 base station 254 determines that there is a change in the second channel list in relation to the first channel list transmitted in system information message illustrated with arrow 203. In response, at time T4 base station 254 may transmit a paging message comprising an indicator for system information modification to mobile node 250. The paging message may be received by any mobile node within the same cell. The paging message may be transmitted using the Physical Downlink Control Channel (PDCCH) in a common area decoded by any mobile node within the same cell. In response, mobile node 250 prepares to receive the second channel list in a next modification period for system information that follows the current modification period 260. At time T5 the verification timer expires and mobile node 250 starts a Self-Contact Timer (SCT) , illustrated in Fig- ure 2 with abbreviation SCT. At the expiry of SCT mobile node 250 may send a connection verification request signal to base station 254 to obtain information on at least one of the status of at least one channel comprised in the channel list, within which mobile node 250 is transmitting, and the second channel list. The status comprises the vacancy of the at least one channel. At time T6 base station 254 transmits a second system information message to mobile node 250 comprising a SIB of SIB type 14, which comprises the sec- ond channel list, as illustrated with arrow 205. The second system information message is transmitted in a radio frame number whose SFN mod p = 0 and in a sub- frame# a. In response to receiving system information message illustrated with arrow 205, mobile node 250 stops the self-contact timer. Further, mobile node 250 starts verification timer. At time T8, the verification timer expires and mobile node 250 starts the self-contact timer. At time T9 the self-contact timer also expirqs and mobile node perform random access procedure, establishes a signaling radio bearer with base station 254 and sends an information request message to base station 254, as illustrated with arrow 206. The information request message may be seen to comprise a connection verification request signal. Mo- bile node 250 also starts a Stop-Working-Timer (SWT) , referred to in Figure 2 with abbreviation SWT. In response, mobile node 250 receives from base station 254 an information response message comprising a third channel list. When receiving the information response message, mobile node 250 stops the SWT timer. At some later point in time, mobile node uses the third chan- nel list to determine at least one radio resource within at least one channel indicated as vacant and optionally indicated as having low load. The determined at least one channel is used by mobile node 250 to start transmitting at least one signal on at least one radio resource comprised in the at least one channel to mobile node 252 using device-to-device transmission, as illustrated with arrow 208.

In one embodiment of the invention, modification period may also be called a system information modification period.

In one embodiment of the invention, the modification period P_MP is calculated as P_MP = M_PC * D_PC / 10 ms, where M_PC is a modification period coefficient and Dpc is a default paging cycle. The M_PC may be signaled in a SIB type 2 and may have, for example, values 1, 2, 4 and 8. The default paging cycle may also be signaled in SIB type 2 and may have, for example, values 320 ms, 640 ms, 1280 ms, 2560 ms , SIB type 2 is also signaled in a System Information (SI) message from the base station 254 to mobile node 250.

In one embodiment of the invention, modification period 260, or■ the periodicity p of SI messages comprising SIB type 14 or any SI message comprising channel information, is set to have a duration that is shorter than a time, in which transmission in a channel indicated as no longer vacant by the frequency band database for base station 254 or by spectrum sensing performed by base station 254, must be stopped by the mobile node 250. The duration may be less than 2 seconds.

In one embodiment of the invention, modification period 260, or the periodicity p of SI messages comprising SIB type 14 or any SI message comprising channel information, is set to have a duration, which, when added to the periodicity of the enquiries of the frequency bands database by base station 254, does not exceed a time set as a maximum periodicity for enquiring of a frequency bands database, for example, a TVWS database, by a mobile node or Mode II device.

In one embodiment of the invention, modification period 260 is specific for the system information messages comprising channel lists, such as first channel list and second channel list.

In one embodiment of the invention, modification period 260 is at the start or during a radio frame number whose SFN mod p - 0, wherein p is the periodicity in radio frames.

In one embodiment of the invention, base station 254 does not wait until the end of the current modification period 260 and start of the next modification period before it transmits the second system information message to mobile node 250 comprising a SIB of SIB type 14, which comprises the second channel list, as illustrated with arrow 205. The second system information message may still be transmitted in a radio frame number whose SFN mod p = 0 and in a sub- framei a.

In one embodiment of the invention, the use of at the least the radio resource comprised in the at least one channel may be reported by mobile node 250 to base station 254 in order for the base station to be able to determine the load situation on the at least one channel comprising the at least one radio resource. Further, mobile node 250 may report to base station 254 that it has ceased to use the at least one radio resource in the at least one channel in order for base station 254 to know the changed load situation on the at least one channel that comprised the at least one radio resource. The reporting may also be performed from mobile node 252 instead of mobile node 250.

In one embodiment of the invention, the at least one radio resource assigned for device-to-device communication uses LTE TDD transmission. The transmission may use OFDMA. The transmission may also use SC- FDMA in one embodiment of the invention.

In one embodiment of the invention, the local device, that is, mobile nodes utilize their OFDM- transmitter/receiver for communication in adjacent TV channels during corresponding downlink transmission. The reason is that the Rx device could use the LTE DL receiver for receiving. That would make possible also the PDCCH decoding of corresponding downlink transmission and receiving, for example, common control information for local, that is, device-to-device communication .

The embodiments of the invention described hereinbefore in association with Figures 1 and 2 may be used in any combination with each other. Several of the embodiments may be combined together to form a further embodiment of the invention.

Figure 3 is a flow chart illustrating a method for transmitting information on unused and used frequency bands from a base station in one embodiment of the invention.

At step 300 a base station determines its present geographic location, for example, using a satellite positioning system such as, for example, GPS. The present location may also be determined from a memory of the base station.

At step 302 the base station provides the geographic location to a frequency bands database and receives first information on at least one channel from the frequency bands database. The base station may form a first channel list using the first information, the first channel list comprising at least one channel entry, the channel entry comprising information on a channel.

At step 304 the base station transmits a system information message to at least one mobile node using the first information received from the database.

At step 306 the base station determines the elapsing of a predefined time. The predefined time may be set to be smaller than pr equal to the time in which a fixed TVBD or Mode II TVBD must contact a TV bands database to obtain updated information on the current status of the channels in the first channel list entries. Alternatively, the predefined time may be set to be smaller than or equal to the time in which a fixed TVBD or Mode II TVBD must scan the fre- quencies for signals exceeding a predefined power threshold on the channels listed in the first channel list entries.

At step 308 the base station obtains obtain^¬ ing second information on at least one channel from the frequency bands database, in response to the elapsing of the predefined time. Alternatively, in response to the elapsing of the predefined time scan the frequencies for at least one signal exceeding a predefined power threshold on the channels listed in the first channel list entries and obtains second information by marking channels where signals were detected as used. The base station compares the first information to the second information.

At step 310 the base station pages the at least one mobile node, if the comparison revealed changed information in the second information in relation to the first information. The paging may comprise an indicator for modified system information.

In one embodiment of the invention, at step 312 the base station waits until system information modification period changes. The system information modification period may enable mobile nodes not to re- ceive at least system information messages until the modification period changes. The mobile nodes may be in discontinuous reception state at least during scheduling times of system modification information messages until the modification period changes.

At step 314 the base station forms a second channel list using the second information, the second channel list comprising at least one channel entry, the channel entry comprising information on a channel. The base station transmits the second channel list in a second system information message to the at least one mobile node.

Thereupon, the method is finished.

Figure 4 is a flow chart illustrating a method for receiving information on unused and used frequency bands to a mobile node in one embodiment of the invention.

At step 400 a mobile node receives a first channel list in a first system information message from a base station. The mobile node may extract the first channel list from the first system information message .

At step 402 the mobile node transmits at least one signal to a remote node using at least one radio resource comprised in at least one channel indicated as vacant in the first channel list.

At step 406 the mobile node receives a paging from the base station, the paging indicating modified system information. In one embodiment of the invention, the paging message indicates modified system information that must be processed by the mobile node and other mobile nodes without waiting for the change of the modification period for system information. This kind of an indication may be sent, if in a second channel list there is at least one channel entry that indicates that a channel, which was indicated as vacant in the first channel list, is no longer vacant. In one embodiment of the invention, the mobile node is in discontinuous reception state during at least the transmission of at least one system information modification message from the base station. This may mean that the mobile node waits until the start of the next modification period for system information .

In one embodiment of the invention, the mobile node prepares to receive a second system informa- tion message without waiting the change of the modification period for system information.

At step 408 the mobile node receives a second channel list in a second system information message from the base station.

At step 410 the mobile node determines whether there is ongoing or scheduled transmission from the mobile node using the at least one radio resource comprised in the at least one channel indicated as vacant in the first channel list and indicated as no longer vacant in the second channel list.

At step 412 the mobile node stops the transmission in case there is ongoing or scheduled transmission from the mobile node using the at least one radio resource comprised in the at least one channel indicated as vacant in the first channel list and indicated as no longer vacant in the second channel list.

Thereupon, the method is finished.

Figure 5 is a block diagram illustrating an apparatus in one embodiment of the invention. In Fig- ure 5 there is an apparatus 500, which is, for example, a mobile node, user equipment, a handset, a cellular phone, a mobile terminal, an Application Specific Integrated Circuit (ASIC), a chip or a chipset. Appara^¬ tus 500 may correspond to a mobile node illustrated in Figures 1, 2, 3 and 4. The internal functions of mobile node 500 are illustrated with a box 502. Mobile node 500 may comprise at least one antenna 510. There may be multiple input and output antennas. In association with mobile node there is Radio Frequency (RF) circuit 512. RF circuit 512 may be also any circuit or may be referred to as circuit 512. RF circuit 512 may comprise multiple subordinate RF circuits or other circuits. RF circuit 512 or a number of circuits comprised in RF circuit 512 may also be referred to as a receiver/transmitter. There may be multiple receivers and transmitters in mobile node 500. RF circuit 512 is communicatively connected to at least one processor 514. Connected to processor 514 there may be a first memory 520, which is, for example, a Random Access Memory (RAM) . There may also be a second memory 522, which may be a non-volatile memory, for example, an optical or magnetic disk. There may also be a User Interface (UI) 516 and a display 518. In memory 520 there may be stored software relating to functional entities 532 and 534. An RF entity 532 may communicate with RF circuit 512 to perform radio resource allocation, de-allocation, signaling plane and user plane data transmission and reception. RF entity 532 may receive system information messages via a protocol stack 534. RF entity 532 also may perform device-to-device transmission. Protocol stack entity 534 comprises control plane protocol functions related to the interface towards an eNB or any base station. RF circuit 512 may comprise the transmitter for SC-FDMA and the receiver and transmitter for OFD A. RF circuit 512 may also comprise a receiver for SC-FDMA.

When the at least one processor 514 executes functional entities associated with the invention, memory 520 may comprise entities such as, any of the functional entities 532 and 534. The functional entities within apparatus 500 illustrated in Figure 5 may be implemented in a variety of ways. They may be implemented as processes executed under the native operating system of the network node. The entities may be implemented as separate processes or threads or so that a number of different entities are implemented by means of one process or thread. A process or a thread may be the instance of a program block comprising a number of routines, that is, for example, procedures and functions. The functional entities may be implemented as separate computer programs or as a single computer program comprising several routines or functions implementing the entities. The program blocks are stored on at least one computer readable medium such as, for example, a memory circuit, memory card, magnetic or optical disk. Some functional entities may be implemented as program modules linked to another functional entity. The functional entities in Figure 5 may also be stored in separate memories and executed by separate processors, which communicate, for example, via a message bus or an internal network within the network node. An example of such a message bus is the Peripheral Component Interconnect (PCI) bus.

Figure 6 is a block diagram illustrating a base station in one embodiment of the invention. In Figure 6 there is a base station 600, which is, for example, a base station server, an Evolved Node B (eNodeB) , an E-UTRAN Node B, a Node B, an Application Specific Integrated Circuit (ASIC) , a chip or a chipset. Base station 600 may correspond to a base station illustrated in Figures 1, 2, 3 and 4. The internal functions of base station 600 are illustrated with a box 602. Base station 600 may comprise at least one antenna 610. There may be multiple input and output antennas. In association with base station there is at least one transmitter 612. At least one of the at least one transmitter 612 may also comprise or have associated with it a receiver (not shown) . Each of the at least one transmitter may comprise at least one Radio Frequency (RF) circuit (not shown) . The RF circuit may be also any circuit or may be referred to as cir- cuit. The at least one transmitter 612 is communicatively connected to at least one processor 614. Connected to processor 614 there may be a first memory 620, which is, for example, a Random Access Memory (RAM) . There may also be a second memory 622, which may be a non-volatile memory, for example, an optical or magnetic disk. In memory 620 there may be stored software relating to functional entities 632 and 634. An RF entity 632 may communicate with the at least one transmitter 612 to perform radio resource allocation, de-allocation, signaling plane and user plane data transmission and reception. RF entity 632 may transmit system information messages via a protocol stack 634. RF entity 632 also may perform enquiries to a frequency bands database, for example, using a separate protocol stack such as TCP/IP (not shown} . Protocol stack entity 634 comprises control plane protocol functions related to the interface towards at least one mobile node. Each of the at least one transmitter 612 may comprise a transmitter for OFDMA and may also comprise or be communicatively connected to a receiver for SC-FDMA.

When the at least one processor 614 executes functional entities associated with the invention, memory 620 may comprise entities such as, any of the functional entities 632 and 63 . The functional entities within base station 600 illustrated in Figure 6 may be implemented in a variety of ways. They may be implemented as processes executed under the native operating system of the network node. The entities may be implemented as separate processes or threads or so that a number of different entities are implemented by means of one process or thread. A process or a thread may be the instance of a program block comprising a number of routines, that is, for example, procedures and functions. The functional entities may be implemented as separate computer programs or as a single computer program comprising several routines or functions implementing the entities. The program blocks are stored on at least one computer readable medium such as, for example, a memory circuit, memory card, magnetic or optical disk. Some functional entities may be implemented as program modules linked to another functional entity. The functional entities in Figure 5 may also be stored in separate memories and executed by separate processors, which communicate, for example, via a message bus or an internal network within the network node. An example of such a message bus is the Peripheral Component Interconnect (PCI) bus.

The embodiments of the invention described hereinbefore in association with Figures 1, 2, 3, 4, 5 and 6 may be used in any combination with each other. Several of the embodiments may be combined together to form a further embodiment of the invention.

The exemplary embodiments of the invention can be included within any suitable device, for example, including any suitable servers, workstations, PCs, laptop computers, PDAs, Internet appliances, handheld devices, cellular telephones, wireless devices, other devices, and the like, capable of performing the processes of the exemplary embodiments, and which can communicate via one or more interface mechanisms, including, for example, Internet access, telecommunications in any suitable form (for instance, voice, modem, and the like) , wireless communications media, one or more wireless communications networks, cellular communications networks, 3G communications networks, 4G communications networks Public Switched Telephone Network (PSTNs), , Packet Data Networks (PDNs) , the Internet, intranets, a combination thereof, and the like.

It is to be understood that the exemplary embodiments are for exemplary purposes, as many variations of the specific hardware used to implement the exemplary embodiments are possible, as will be appre- ciated by those skilled in the hardware art(s). For example, the functionality of one or more of the components of the exemplary embodiments can be implemented via one or more hardware devices, or one or more software entities such as modules.

The exemplary embodiments can store information relating to various processes described herein. This information can be stored in one or more memories such as a hard disk, optical disk, magneto-optical disk, RAM, and the like. One or more databases can store the information regarding cyclic prefixes used and the delay spreads measured. The databases can be organized using data structures (e.g., records, tables arrays, fields, graphs, trees, lists, and the like) included in one or more memories or storage devices listed herein. The processes described with respect to the exemplary embodiments can include appropriate data structures for storing data collected and/or generated by the processes of the devices and subsystems of the exemplary embodiments in one or more databases.

All or a portion of the exemplary embodiments can be implemented by the preparation of one or more application-specific integrated circuits or by interconnecting an appropriate network of conventional component circuits, as will be appreciated by those skilled in the electrical art(s).

As stated above, the components of the exemplary embodiments can include computer readable medium or memories according to the teachings of the present inventions and for holding data structures, tables, records, and/or other data described herein. Computer readable medium can include any suitable medium that participates in providing instructions to a processor for execution. Such a medium can take many forms, including but not limited to, non-volatile media, volatile media, transmission media, and the like. Nonvolatile media can include, for example, optical or magnetic disks, magneto-optical disks, and the like. Volatile media can include dynamic memories, and the like. Transmission media can include coaxial cables, copper wire, fiber optics, and the like. Transmission media also can take the form of acoustic, optical, electromagnetic waves, and the like, such as those generated during radio frequency (RF) communications, infrared (IR) data communications, and the like. Common forms of computer-readable media can include, for example, a floppy disk, a flexible disk, hard disk, magnetic tape, any other suitable magnetic medium, a CD-ROM, CDRW, DVD, any other suitable optical medium, punch cards, paper tape, optical mark sheets, any other suitable physical medium with patterns of holes or other optically recognizable indicia, a RAM, a PROM, an EPROM, a FLASH-EPROM, any other suitable memory chip or cartridge, a carrier wave or any other suitable medium from which a computer can read.

While the present inventions have been described in connection with a number of exemplary embodiments, and implementations, the present inventions are not so limited, but rather cover various modifications, and equivalent arrangements, which fall within the purview of prospective claims.

It is obvious to a person skilled in the art that with the advancement of technology, the basic idea of the invention may be implemented in various ways. The invention and its embodiments are thus not limited to the examples described above; instead they may vary within the scope of the claims.

Claims

WHAT IS CLAIMED IS:

1. A method, comprising:

determining a geographic location of a base station;

providing the geographic location to a frequency bands database;

receiving first information on at least one channel from the frequency bands database;

forming a first channel list using the first information, the first channel list comprising at least one channel entry, the channel entry comprising information on a channel;

transmitting the first channel list in a first system information message to at least one mobile node determining the elapsing of a predefined time;

obtaining second information on at least one channel from the frequency bands database, in response to the elapsing of the predefined time;

comparing the first information to the second information;

paging the at least one mobile node in response to the comparison revealing changed information in the second information in relation to the first information, the paging indicating modified system information;

forming a second channel list using the second_. information, the second channel list comprising at least one channel entry, the channel entry comprising information on a channel; and

transmitting the second channel list in a second system information message to the at least one mobile node .

2. The method according to claim 1, wherein a change of system information modification period is determined before the second channel list is transmitted in a second system information message to the at least one mobile node.

3. The method according to claim 1, the method further comprising:

transmitting a third system information message to at least one mobile node, the third system information message comprising information on the periodicity of the first system information message and the second system information message.

4. The method according to claim 1, the method further comprising:

determining at least one target mobile node, which is transmitting or permitted to transmit, on the at least one channel;

determining whether the number of mobile nodes is below a predefined threshold value; and

transmitting the first channel list as a dedicated signaling message to the at least one target mobile node .

5. The method according to claim 4, the method further comprising:

bypassing the transmitting of the first system information message, the paging of the at least one mobile node, and transmitting of the second system information message.

6. The method according to claim 4, the method further comprising:

bypassing the transmitting of the first channel list in the first system information message and bypassing the transmitting of the second channel list in the second system information message.

7. The method according to claim 1, the method further comprising:

determining load on each vacant channel of the first channel list; and

adding information on the load to each channel en- try.

8. The method according to claim 7, wherein the step of determining load on each vacant channel of the first channel list further comprises:

determining the number of mobile nodes transmit- ting or permitted to transfer on each vacant channel of the first channel list.

9. The method according to claim 1, the method further comprising:

transmitting the first system information message and the second system information message using an orthogonal frequency division multiple access transmitter .

10. The method according to claim 1, wherein the base station comprises a Long-Term Evolution (LTE) Evolved Node B.

11. The method according to claim 1, wherein the frequency bands database is a television bands database and the at least one channel is a television channel .

12. A method, comprising:

receiving a first channel list in a first system information message from a base station in a mobile node;

extracting the first channel list from the first system information message;

transmitting, from the mobile node, at least one signal to a remote node using at least one radio resource comprised in at least one channel indicated as vacant in the first channel list;

receiving a paging from the base station, the paging indicating modified system information;

receiving a second channel list in a second system information message from the base station;

determining whether there is ongoing or scheduled transmission from the mobile node using the at least one radio resource comprised in the at least one channel indicated as vacant in the first channel list and indicated as no longer vacant in the second channel list; and

stopping the transmission in case there is ongoing or scheduled transmission from the mobile node using the at least one radio resource comprised in the at least one channel indicated as vacant in the first channel list and indicated as no longer vacant in the second channel list.

13. The method according to claim 12, the method further comprising:

determining that the remote node is within a transmission range of the mobile node.

14. The method according to claim 12, the method further comprising:

transmitting, from the mobile node, a first test signal to the remote node; and

increasing transmission power for a second test signal to the remote node, in the absence of a response from the remote node.

15. The method according to claim 12, the method further comprising:

requesting a reservation of the at least one radio resource .

16. The method according to claim 15, the method further comprising:

detecting a success of the reservation of the at least one radio resource.

17. The method according to claim 15, wherein the reservation is requested using a radio resource comprised in the at least one channel indicated as vacant in the first channel list.

18. The method according to claim 16, wherein the detecting of the success of the reservation is performed by receiving a confirmation of the reserva- tion on a radio resource comprised in the at least one channel indicated as vacant in the first channel list.

19. The method according to claim 15, wherein the reservation is requested from the base station.

20. The method according to claim 12, wherein the remote node is a mobile node.

21. The method according to claim 12, wherein the mobile node is a Long-Term Evolution User Equipment .

22. A base station, comprising:

at least one transmitter configured to transmit a first system information message and a second system information message; and

at least one processor configured

to determine a geographic location of the base station,

to provide the geographic location to a frequency bands database,

to receive first information on at least one channel from the frequency bands database,

to form a first channel list using the first in- formation, the first channel list comprising at least one channel entry, the channel entry comprising information on a channel,

to transmit the first channel list in the first system information message to at least one mobile node, to determining the elapsing of a predefined time, to obtain second information on at least one channel from the frequency bands database, in response to the elapsing of the predefined time,

to compare the first information to the second in- formation,

to page the at least one mobile node in response to the comparison revealing changed information in the second information in relation to the first information, the paging indicating modified system informa- tion,

to form a second channel list using the second information, the second channel list comprising at least one channel entry, the channel entry comprising information on a channel, and

to transmit the second channel list in the second system information message to the at least one mobile node .

23. An apparatus, comprising:

at least one processor configured

to receive a first channel list in a first system information message from a base station in the appara- tus,

to extract the first channel list from the first system information message,

to transmit, from the apparatus, at least one signal to a remote node using at least one radio resource comprised in at least one channel indicated as vacant in the first channel list,

to receive a paging from the base station, the paging indicating modified system information,

to receive a second channel list in a second sys- tern information message from the base station,

to determine whether there is ongoing or scheduled transmission from the mobile node using the at least one radio resource comprised in the at least one channel indicated as vacant in the first channel list and indicated as no longer vacant in the second channel list, and

to stop the transmission in case there is ongoing or scheduled transmission from the mobile node using the at least one radio resource comprised in the at least one channel indicated as vacant in the first channel list and indicated as no longer vacant in the second channel list.

24. A system comprising the apparatus according to claim 23 and the base station according to claim 22.

25. A computer program comprising code adapted to cause the following when executed on a data-processing system:

determining a geographic location of a base sta- tion;

providing the geographic location to a frequency bands database;

transmitting the first channel list in a first system information message to at least one mobile node; determining the elapsing of a predefined time;

comparing the first information to the second information;

paging the at least one mobile node in response to the comparison revealing changed information in the second information in relation to the first informa- tion, the paging indicating modified system information;

forming a second channel list using the second information, the second channel list comprising at least one channel entry, the channel entry comprising infor- mation on a channel; and

26. The computer program according to claim 25, wherein said computer program is stored on a computer readable medium.

27. A computer program comprising code adapted to cause the following when executed on a data-processing system:

extracting the first channel list from the first system information message;

transmitting, from the mobile node, at least one signal to. a remote node using at least one radio resource comprised in at least one channel indicated as vacant in the first channel list;

28. The computer program according to claim 27, wherein said computer program is stored on a computer readable medium.