JPH03104429A - Random access control system - Google Patents

Abstract

PURPOSE:To improve the throughput of the entire radio zone by separating its own information from a burst signal from a relevant sector, measuring a reception level by each measuring means of a base station and deciding transmission enable or transmission inhibit to each sector. CONSTITUTION:When the necessity of transferring an incoming information message is caused in a mobile station, a signal separate circuit 36 separates an information notice part relating to transmission enable for each sector from a data from a base station demodulated at a demodulation circuit 35 and the information notice part is inputted to a transmission control circuit 32. When transmission enable information corresponding to an in-zone sector of the mobile station is enabled of transmission, the transmission is started from a head burst in a required timing. A notice information control circuit 23 fetches information relating to a length of an incoming burst signal from sector depending transmitter-receivers 211-216, an outgoing mobile station identifier and a burst reception level as input information and compares the reception levels to generate transmission enable or inhibit information for each sector and informs it to each sector transmitter-receiver 21.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention is used in a random access control system for mobile communications. In particular, it relates to a signal transmission method when transmitting and receiving signals between a base station and a plurality of mobile stations.

[Conventional technology]

FIG. 10 is a diagram showing the arrangement of sectors in the wireless zone.

FIG. 11 shows a downlink channel format of a conventional random access control system.

Conventionally, random access methods in which a plurality of mobile stations randomly access a base station include the slotted Aloha method and the ICMA method (Idle Signal Casting Method).
ng Multiple Access), etc. The latter is a method that controls mobile station transmission by broadcasting permission or prohibition of transmission from the base station and avoids collisions between signals from multiple mobile stations, so it provides superior transmission compared to the former. This is a method of showing characteristics.

On the other hand, in order to effectively utilize frequency resources, multiple directional antennas are installed at a base station, the area covered by one directional antenna is defined as a sector, and multiple antennas and sectors constitute a wireless zone. There is a method. FIG. 10 shows the sector configuration of a wireless zone, and shows a case where one zone has seven sectors.

In the conventional system, the communication channel uses an independent frequency, antenna, and transceiver for each sector in the configuration shown in FIG. However, the control channel covers one entire wireless zone, that is, all sectors, with one omnidirectional antenna of the base station, and even if the antenna is one of one frequency ball transceiver, or the antenna is a directional antenna for each sector. Omnidirectional transmission and reception is performed using one frequency and one transmitter/receiver common to all sectors.

Let us consider the case where the ICMA method is performed under this structure.

FIG. 11 is a diagram showing a conventional downlink channel format. As shown in Fig. 11, there is no information broadcast part regarding transmission permission for each sector, but an information broadcast part regarding transmission permission that is the same for all sectors is provided in the down channel, so that transmission permission or prohibition information is shared common to all sectors. inform. When a mobile station within a zone transmits a signal to a base station, it transmits signals in all sectors within the zone to prohibit signal transmission from other mobile stations in order to ensure omnidirectional transmission and reception by one transceiver. Notify all sectors that this is not possible.

[Problem to be solved by the invention]

However, in such conventional random access control systems, signal transmission for all mobile stations within a zone is handled by a common base station transceiver, which increases the traffic related to random access and increases the signal collision rate. The disadvantages were that the signal non-reception rate at the base station was high and the throughput of the entire wireless zone was low.

On the other hand, there is a method that uses a different frequency for each sector and performs the ICMA method for each sector, but the frequency utilization rate per frequency is low, each zone requires as many frequencies as the number of sectors, and many frequencies are used for control channels. There were drawbacks that made it necessary.

The present invention solves the above-mentioned drawbacks and aims to provide a highly efficient random access control scheme under a sectorized zone structure.

[Means for solving problems]

The present invention includes a plurality of mobile stations including a mobile station transceiver and a base station including a base station transceiver and communicating with the plurality of mobile stations, a wireless zone is divided into a plurality of sectors, The base station transceiver includes a different receiving means for each sector, and each mobile station transceiver includes a notification means for notifying the base station of own station information,
Each of the above receiving means is a random access control means including a first separation means for separating the notified own station information from the burst signal from the corresponding sector, and each of the above receiving means is a random access control means that separates the notified own station information from the burst signal from the corresponding sector. The base station transceiver includes a determining means for determining information regarding transmission permission for each sector based on the output of each of the first separating means and the measurement results of each of the measuring means. and broadcasting means for broadcasting the determined information to each of the sectors, and each of the mobile station transceivers includes a second separation unit that separates information for the sector in which the mobile station is located from the output information of the broadcasting means. and a control means for controlling transmission to the base station based on the separated information.

Further, the present invention includes a plurality of mobile stations including a mobile station transceiver and a base station including a base station transceiver and communicating with the plurality of mobile stations, and the wireless zone is divided into a plurality of sectors. In the random access control means, the base station transceiver includes a different receiving means for each of the sectors, and each of the mobile station transceivers transmits information indicating the sector in which the own station is located to the base station. Each of the receiving means includes a first separation means for separating the notified own station information from the burst signal from the corresponding sector, and the base station transceiver teeth,
Each of the mobile station transceivers includes a determining means for determining information regarding transmission permission for each of the sectors based on the output of each of the first separating means, and a notifying means for notifying the determined information to each of the sectors; may include a second separation means for separating information regarding the sector in which the own station is located from the output information of the notification means, and a control means for controlling transmission to the base station based on this separated information. .

[Effect]

Each first separating means of the base station separates own station information from the burst signal from the corresponding sector, and each measuring means of the base station measures the reception level. The determining means of the base station determines whether to permit or prohibit transmission for each sector based on the separated signals and the magnitude of the measured reception level. The broadcasting means of the base station broadcasts the information determined by the determining means to each sector. The second separation means of each mobile station separates information regarding the sector in which the mobile station is located from the output information of the notification means. The control means of each mobile station controls transmission to the base station based on this separated information. Through the above operations, the throughput of the entire wireless zone can be increased.

In addition, instead of measuring the reception level, each mobile station notifies the base station of its own information including information about the sector in which it is located, and the base station broadcasts information regarding transmission permission to each sector based on this information. Similarly, throughput can be increased.

〔Example〕

Embodiments of the present invention will be described with reference to the drawings. 1st
The figure is a block diagram of a random access control system according to an embodiment of the present invention. FIG. 2 is a block diagram of a sector-by-sector transceiver of the random access control system of the present invention. FIG. 1 shows a case where a base station is provided with a transceiver for each sector. In FIGS. 1 and 2, the random access control method includes a plurality of mobile stations including a mobile station transceiver,
The wireless zone is divided into a plurality of sectors, and the base station transceiver performs different transmission and reception for each sector. As a means, a sector-by-sector transceiver 211
~216 and antenna 11. ~116, a signal selection circuit 24, and a signal distribution circuit 25, and each mobile station transceiver includes an encoding circuit 3l, a modulation circuit 33, a transmission/reception distribution unit 34, an antenna 38, a demodulation circuit 35, and a decoding circuit 37. The encoding circuit 31, the modulation circuit 33, the transmitter/receiver 34, and the antenna 38 include notification means for notifying the base station of its own information, and the transmitter/receiver 21 for each sector
includes a signal separation circuit 14 as a first separation means for separating the notified own station information from the burst signal from the corresponding sector.

Here, the feature of the present invention is that the sector-by-sector transceiver 21 includes a reception level measuring circuit 16 as a measuring means for measuring the receiving state of the notified own station information, and the base station transceiver A broadcast information control circuit 23 is included as a determining means for determining information regarding transmission permission for each sector based on the output of the separation circuit 14 and the measurement result of the reception level measurement circuit 16, and the transceiver for each sector transmits this determined information. A signal multiplexing circuit 18 is included as a notification means for notifying each sector, and each mobile station transceiver serves as a second separation means for separating information regarding the sector in which the own station is located from the output information of the signal multiplexing circuit 18. It includes a signal separation circuit 36 and a transmission control circuit 32 as a control means for controlling transmission to the base station based on the separated information.

The operation of the random access control system having such a structure will be explained.

FIG. 3 is a diagram showing sectors of the random access control system of the present invention and antennas corresponding to the sectors of a base station. FIG. 4 is a diagram showing the horizontal plane directivity of the antenna of the sector-by-sector transceiver of the random access control system of the present invention. Fifth
The figure shows the format of a downlink channel transmitted from a base station using the random access control system of the present invention. FIG. 6 is a diagram showing the reception level at each sector transceiver in the random access control system of the present invention. FIG. 7 shows the format of the upstream channel of the random access control system of the present invention. In FIG. 7, 71 is a preamble, 72 is information regarding the burst length, and 74 is other information.

First, the operations of the mobile station and base station when transferring uplink messages will be explained. In Figure 1, when a mobile station needs to transfer an uplink information message, the encoding cycle i
i! At 831, processing such as error correction encoding is performed as necessary, and the signal is input to the transmission control circuit 32 and waits for transmission. The data from the base station, which has passed through the antenna 38 and the transmission/reception distributor 34 and has been demodulated by the demodulation circuit 35, is sent to the fifth signal separation circuit 36.
The information notification portions 61 to 66 regarding transmission permission for each sector shown in the figure are separated and input to the transmission control circuit 32 manually. When the transmission permission information corresponding to the sector in which the mobile station is located indicates that transmission is possible, transmission is started from the first burst at an appropriate timing. However, the mobile station must know in advance the sector in which it is located. On the base station side, a signal from a mobile station is input to a demodulation circuit 13 and a reception level measurement circuit 16 through an antenna 11 and a transmission/reception distributor 12 shown in FIG. The output of the demodulation circuit 13 is sent to the signal separation circuit 14, which separates information regarding the signal length of the burst transmitted by the mobile station and the transmission mobile identification number of the burst, and inputs the information to the broadcast information control circuit 23. Other signals are decoded by the decoding circuit 15 and transferred as uplink information. The output of the reception level measuring circuit l6 is transmitted to the broadcast information control circuit 23.

The broadcast information control circuit 23 includes a transceiver 21 for each sector installed for each sector. 216, the information regarding the length of the uplink burst signal, the originating mobile station identifier, and the burst reception level are taken in as manual information, and the sector in which the mobile station that sent the corresponding burst exists is transmitted from each sector-by-sector transceiver 21. Identifies by comparing reception levels, generates transmission permission or prohibition information for each sector based on the identified sector, or compiles it as transmission permission information common to all sectors, and notifies each sector to the transceiver 2l. do. The transmission permission or prohibition information continues for a corresponding burst time period, and the currently transmitting mobile station continues to transmit, but the transmission prohibition signal prohibits other mobile stations from making new transmissions. The originating mobile station identifier is used to identify the burst signal transmitted by the mobile station, and if there is another number that can identify the burst, it may be used.

The signal selection circuit 24 selects one of the duplicate information sent from each sector transceiver 21 and sends it to a higher level. The signal distribution circuit 25 distributes information for each transceiver 2l for each sector. Each sector transmitter/receiver 21 takes in information regarding transmission permission from the broadcast information control circuit 23 as a manual input of the signal multiplexing circuit 18, and transmits permission information broadcast sections 61 to 6 shown in FIG.
6 and sends it to the modulation circuit 17 along with other downlink information as a downlink channel signal. The signal modulated by the modulation circuit 17 is sent to the transmission/reception distributor 12 and the antenna 11.
is transmitted to the mobile station via

Next, the operation of the broadcast information control circuit 23 will be explained using a specific example. Consider the case where a mobile station exists within the sector 42 shown in FIG. 3 and transmits a burst toward the base station.

Since the directivity of the antenna extends to adjacent sectors as shown in FIG. 4, the corresponding burst is received not only by the antenna 52 but also by the antennas 51 and 53. . Transmitter/receiver 21 for each sector,
An example of the reception level of the corresponding burst at 22 is shown in FIG. Since the reception level changes due to the influence of fading in land mobile communications, the corresponding mobile station does not necessarily exist in the sector covered by the antenna with the maximum reception level, but the reception level of the sector with the maximum reception level and adjacent sectors etc. By comparing these with each other, it is possible to identify the corresponding mobile localization area sector. In this embodiment, the reception level of the sector 42 and the reception levels of the sectors 41 and 43 are high, and the reception levels of the sectors 44, 45 and 46 are low, almost "0". This allows the base station to specify that the mobile station is located in the sector 42. Due to the directivity of the antenna, if a mobile station located in sectors 41, 42, 43 transmits and the signal collides with the corresponding burst, there is a high probability that the signal will not be received, so transmission permission for sectors 41, 42, 43 is The information notification portions 61 to 63 are bit-bangs indicating transmission prohibition, thereby suppressing signal transmission from other mobile stations. but,
Even if a mobile station located in sectors 44, 45, or 46 transmits a signal, there is a very small probability that it will collide with a signal transmitted by a mobile station located in sector 42 due to antenna directivity, resulting in non-reception due to interference. Therefore, the transmission permission information notification parts 64, 65, and 66 make a bit bang indicating that transmission is possible, and permit other mobile stations to transmit signals. The bit pattern indicating transmission permission or prohibition continues for the length of the burst currently being received. Therefore, even while the mobile station located in sector 42 is transmitting and receiving signals, the mobile stations located in sectors 44, 45, and 46 of the transmission permission information notification part can transmit and receive signals. .

In this way, even if a mobile station within one sector transmits a signal, it does not broadcast a prohibition signal to all sectors at the same time, but instead determines and broadcasts transmission permission or prohibition for each sector. It becomes possible to transmit multiple signals at the same time on the random access channel, and throughput is improved compared to the conventional case where only one signal at most could be transmitted at the same time per wireless zone.

Furthermore, since the frequency common to all sectors is used, the number of required frequencies can be reduced.

In this example, a method was shown in which the reception level is measured, the sector in which the mobile station is located is identified, and transmission prohibition is notified to adjacent sectors. If the gain is sufficiently large compared to the gains of sectors other than the own sector, there is no need to notify transmission prohibition to adjacent sectors, and a method may be adopted in which only the serving sector prohibits transmission by other mobile stations. If the gains in sectors other than the own sector cannot be said to be sufficiently small, a method may be adopted in which transmission by other mobile stations in sectors in that direction is prohibited to further reduce the possibility of signal collision.

In addition, the base station does not clearly identify the sector in which the mobile station is located, and instead sets a reception level as a threshold, prohibiting transmission in sectors where the reception level exceeds the threshold, and prohibiting transmission in sectors where the reception level does not exceed the threshold. There is also a method of determining that transmission is possible and notifying the user.

FIG. 8 is a block diagram of a random access control system according to another embodiment of the present invention. The difference from the embodiment shown in FIG. 1 is that a reception level measuring circuit is not provided.

FIG. 9 is a diagram explaining the structure of a burst signal transmitted by a mobile station, in which 71 is a preamble, 72 is information regarding the burst length, 73 is mobile local area sector information, and 74 is a diagram for explaining the structure of a burst signal transmitted by a mobile station.
are bits representing other information.

In the embodiment shown in FIG. 1, the reception level of the signal measured by the transceiver 2t for each sector is compared to identify the sector in which the mobile station is located, but the mobile station does not recognize the sector in which it is located. Therefore, as shown in FIG. 9, the sector information part 73 of the uplink burst tells the base station the sector in which its own station exists, and based on this, the base station performs the same procedure as in the embodiment shown in FIG. Information regarding transmission permission for each sector can be determined. In the method of the embodiment shown in FIG. 8, fluctuations in reception level due to land mobile fading do not affect much
The base station side can uniquely determine the sector of the signal transmitting mobile station. Further, since there is no need to collect reception level information from each sector, there is an advantage that the amount of information transferred to the broadcast information transfer circuit is small, and the load on the device is reduced.

As explained above, in the first embodiment and the second embodiment,
Although we have explained the case where a transmitter/receiver is installed in each sector, since the information sent from the base station to the mobile station is common to all sectors in the wireless zone, this can also be achieved by using a transmitter common to all sectors. is possible.

Furthermore, although the zone/sector structure has been described, it can generally be applied to a case where a plurality of mobile stations perform random access to a plurality of base station transceivers using the same frequency.

The method by which a mobile station determines the sector in which it is located is to use a frequency including a control channel assigned to each wireless zone from a base station and a sector individual frequency assigned to each sector to be transmitted to each zone and sector via a directional antenna. There is a method in which the mobile station transmits data to the mobile station and measures the received level at the mobile station.

This method will be disclosed in an invention (name, mobile station sector identification method) filed simultaneously by the same applicant as this application, but the gist is: multiple mobile stations including mobile station transceivers, and a base station that includes a station transmitting/receiving rock and communicates with the plurality of mobile stations, each of the plurality of wireless zones is divided into sectors, and the base station transceiver is assigned to each of the wireless zones. Each mobile station transceiver includes a first transmitting/receiving means for transmitting/receiving a frequency signal including a control channel via a directional antenna, and each mobile station transceiver includes:
In the mobile station sector determination method including second transmitting/receiving means for transmitting/receiving a signal at a frequency including the control channel, each of the first transmitting/receiving means transmits a signal at a sector individual frequency assigned to each sector. The second transmitting/receiving means includes a transmitting means for transmitting through a directional antenna, and each of the second transmitting/receiving means includes a receiving means for receiving a signal of a frequency individual to each sector, and a signal of a frequency including the received control channel and an individual transmitter for each sector. 1. A method for determining a sector in which a mobile station is located, comprising: a measuring means for measuring the reception level of a signal at a frequency; and a determining means for determining its own wireless zone and own sector based on the measurement results of the measuring means.

Further, in the present invention, each of the second transmitting/receiving means transmits a signal of the sector individual frequency of the own sector and a signal of the control channel frequency of the own radio zone according to the own radio zone and the own sector determined by the above-mentioned determining means. and a predetermined threshold value, and detects movement between sectors within the own wireless zone based on the comparison result.

〔Effect of the invention〕

As described above, the present invention has the excellent effect of increasing the throughput of the entire wireless zone.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a random access control system according to an embodiment of the present invention. FIG. 2 is a block diagram of a sector-by-sector transceiver of the random access control system of the present invention. FIG. 3 is a diagram showing sectors of the random access control system of the present invention and antennas corresponding to the sectors of a base station. FIG. 4 is a diagram showing the horizontal plane directivity of the antenna of the sector-by-sector transceiver of the random access control system of the present invention. FIG. 5 shows the format of a downlink channel transmitted from a base station using the random access control system of the present invention. FIG. 6 is a diagram showing the reception level at each sector transceiver in the random access control system of the present invention. FIG. 7 shows the format of the uplink channel of the random access control system of the present invention. FIG. 8 is a block diagram of a random access control system according to another embodiment of the present invention. FIG. 9 is an upstream channel format of a random access control system according to another embodiment of the present invention. FIG. 10 is a diagram showing the structure of sectors in a wireless zone. FIG. 11 shows the downlink channel format of the conventional random access control system. 11, 111-116, 3B... antenna, 12, 3
4... Transmission/reception distributor, 13... Demodulation circuit, l4...
Signal separation circuit, 15...Decoding circuit, 16...Reception level measuring circuit, 17...Modulation circuit, 18...Signal multiplexing circuit, 19...Encoding circuit, 21, 21. ~216
... Transmitter/receiver for each sector, 23... Broadcast information control circuit, 24... Signal selection circuit, 25... Signal distribution circuit,
3l... Encoding circuit, 32... Transmission control circuit, 33
...Modulation circuit, 34...Transmission/reception distributor, 35...Demodulation circuit, 36...Signal separation circuit, 37...Decoding circuit, 41-46...Sector, 5l...Sector 41 A directional antenna provided at the base station for the sector 42, 52... A directional antenna provided at the base station for the sector 42, 53...
・Directional antenna installed at the base station for sector 43,
54... Directional antenna provided in the base station for sector 44, 55... Directional antenna provided in the base station for sector 45, 56... Directional antenna provided in the base station for sector 46 Directional antenna, 57...Mobile station existing in sector 42, 61...Transmission permission information notification part regarding sector 41, 62...Transmission permission information notification part regarding sector 42, 63...Regarding sector 43 Transmission permission information notification part, 64...Transmission permission information notification part regarding sector 44, 65...Transmission permission information notification part regarding sector 45, 66...Transmission permission information notification part regarding sector 46, 67...Others 71... Preamble, 72... Information regarding burst length, 73... Information regarding mobile local area sector, 74... Other information.

Claims (1)

[Claims] 1. A wireless zone includes a plurality of mobile stations including a mobile station transceiver and a base station including a base station transceiver and communicating with the plurality of mobile stations, and a wireless zone has a plurality of sectors. The base station transceiver includes a different receiving means for each sector, and each of the mobile station transceivers includes a notification means for notifying the base station of its own station information; In the random access control means, each receiving means includes a first separation means for separating the notified own station information from the burst signal from the corresponding sector; The base station transceiver includes a measuring means for measuring a reception state, and the base station transceiver has a determining means for determining information regarding transmission permission for each sector based on the output of each of the first separating means and the measurement result of each of the measuring means. , broadcasting means for broadcasting the determined information to each of the sectors, and each of the mobile station transceivers includes second separating means for separating information for the sector in which the mobile station is located from the output information of the broadcasting means. and a control means for controlling transmission to the base station based on the separated information. 2, comprising a plurality of mobile stations including a mobile station transceiver and a base station including a base station transceiver and communicating with the plurality of mobile stations; the wireless zone is divided into a plurality of sectors; The station transceiver includes a random access control means that includes different reception means for each of the sectors, and each of the mobile station transceivers transmits a mobile station to the base station that includes information indicating the sector in which the mobile station is located. The base station transmitter/receiver includes notification means for notifying the information, each of the receiving means includes first separation means for separating the notified own station information from the burst signal from the corresponding sector, and the base station transceiver Each of the mobile station transceivers includes a determining means for determining information regarding transmission permission for each sector based on the output of the first separating means, and a notifying means for notifying the determined information to each sector, It is characterized by comprising a second separation means for separating information regarding the sector in which the own station is located from the output information of the notification means, and a control means for controlling transmission to the base station based on the separated information. Random access control method.