CN100349493C - Method for reinforcing search under omnidirectional emission sector receiving mode - Google Patents

Abstract

The present invention relates to a multi-path search technique in the field of mobile communication, and discloses a method for reinforcing search under an omnidirectional emission sector receiving mode. Thus, when a terminal under the omnidirectional emission sector receiving mode moves, the dropping probability of the terminal is reduced. In the present invention, although independent polling processing is carried out on each sector just like the prior art, polling results are not independently processed, the polling results are uniformly processed in a radio link set, and the search window position of the three sectors are uniformly adjusted. Thus, the search window position of each radio link and the search window position of the radio link with maximum effective diameter SNR in the radio link set are the same.

Description

A Method of Enhanced Search in Omnidirectional Transmitting Sector Receiving Mode

technical field

The invention relates to the multipath search technology in the field of mobile communication, in particular to the enhanced multipath search technology under the receiving mode of the omnidirectional transmitting sector.

Background technique

With the development of mobile communications, the third generation of mobile communications (The Third Generation, referred to as "3G") is gradually commercialized. In the initial stage of 3G network construction, the requirements for network capacity are generally not high, but the network coverage will directly affect the user experience and become one of the most important criteria for users to judge network quality, thus directly affecting the brand of mobile operators Image and user loyalty. How to build a 3G network with effective coverage and capacity that can evolve smoothly with the increase of the number of users at a lower cost has become one of the most concerned issues for mobile operators.

Omni Transmit Sector Receive ("OTSR") is a solution proposed under this background. There are usually two traditional coverage methods of traditional base stations: omnidirectional and directional. The omnidirectional station uses a power amplifier (Power Amplifier, referred to as "PA"), and its antenna is an omnidirectional antenna; the directional station uses three PAs, and its antenna is a directional antenna. OTSR combines the traditional omnidirectional and directional technologies. The transmission adopts omnidirectional transmission and the reception adopts 3-sector reception, which can reduce the investment on PA without reducing the coverage. Since the gain of the directional antenna is higher than that of the omnidirectional antenna, and the coverage radius is longer, the use of OTSR can reduce the network construction cost and improve the coverage when the capacity requirement is not large in the initial stage of network construction. It should be noted that there is no need to use an additional omnidirectional antenna during transmission, and the downlink power output by the PA can be evenly distributed to three directional antennas through a splitter to realize omnidirectional transmission. This OTSR configuration can reduce the investment in PA as much as possible, and because it also uses directional antennas, its coverage effect is almost equivalent to that of directional stations. With the increase of users, when the base station needs to be expanded, just remove the splitter and add two PAs to upgrade the OTSR to a directional station.

The schematic diagram of the transmission and reception of OTSR is shown in Figure 1. The base station is located at the center of the circle, and when receiving user signals, it receives user signals in three sectors respectively; when the base station sends signals, it sends omnidirectionally within a range of 360°.

In the mobile communication system, since the same transmitted signal can be transmitted through multiple different paths, there is a phenomenon of multipath transmission. Because 3G adopts the Code Division Multiple Access (CDMA) technology that can resist multipath interference, it can use RAKE receiver for multipath diversity reception when receiving, and improve the signal noise ratio (Signal Noise ratio) , referred to as "SNR"). During multipath reception, it is necessary to search for multipath within a range based on the pilot frequency, wherein the range for searching for multipath is called a search window.

When searching for multipath, when the distance between the head and tail paths in the search window is very far, the position of the search window is improper, so that all the effective paths cannot be included in the search window, or new paths appear outside the window, it is usually necessary to use enhanced The search technique searches for multipaths in a large range. Polling technology is a kind of enhanced search technology.

A schematic diagram of a search range for searching multipath by using the polling technology is shown in FIG. 2 . The shaded boxes indicate the range of the normal search window, and the blank boxes indicate the search range of the polling search. Polling is to search for multipath in a larger range than the normal search window, and then adjust the position of the normal search window according to the search results, so as to achieve the purpose of enhancing the multipath reception effect.

In the prior art solution, when the polling technology is used in the OTSR mode, each wireless link in the OTSR mode is independently processed according to the polling algorithm, that is, for a signal transmitted by a terminal, it is separately processed in three sectors. The polling is performed independently to search the multipath, and the positions of the search windows for the wireless links of the same terminal in the three sectors are independent of each other.

It should be noted that, in this paper, it is considered that the same terminal may have wireless links in each sector, and these wireless links together constitute the wireless link set of the terminal.

In practical application, the above solution has the following problem: when the terminal moves in different sectors, it may cause call drop.

The main reason for this situation is that in OTSR mode, when the enhanced multipath search is independently performed on each sector in a polling manner, virtual paths may be generated in some sectors, causing the search window to deviate from the normal position , so that when the terminal moves to these sectors, it will not be able to search for multipaths, resulting in link out-of-sync, resulting in call drop. For example, in Figure 1, when the terminal is at point A at the junction of two sectors, since the coverage areas of the three antennas are different, the quality of the wireless link of the terminal in the sector where point B is located will be relatively poor. It is possible that there is no multipath at all, but if the sector searches for a virtual path during polling, causing the normal search window of the terminal in this sector to deviate from the normal position of the search window, then when the terminal moves from point A to point B When this point is reached, the multipath cannot be searched, resulting in link out-of-synchronization and eventually call drop.

Contents of the invention

In view of this, the main purpose of the present invention is to provide a method for enhanced search in the receiving mode of the omnidirectional transmitting sector, so that when the terminal in the OTSR mode moves, the probability of the terminal dropping calls is reduced.

In order to achieve the above object, the present invention provides a method for enhanced search in receiving mode of omnidirectional transmitting sector, comprising the following steps:

A For each terminal, each wireless link in its wireless link set is polled separately, and the wireless link with an effective path and the largest signal-to-noise ratio in the wireless link set is obtained;

B uniformly adjusts the search window position of each wireless link in the wireless link set to be the same as the search window position determined by polling for the wireless link with the largest signal-to-noise ratio.

Wherein, the step A includes the following sub-steps:

After A1 polls one of the wireless links in the wireless link set, if a valid path is found, then go to step A2, otherwise go to step A4;

A2 judges whether the wireless link is the first polled wireless link with an effective path in the wireless link set, if so, record the multipath information of the wireless link as historical information, otherwise enter step A3;

A3 judges whether the signal-to-noise ratio of the wireless link is greater than or equal to the signal-to-noise ratio in the historical information, if so, updates the historical information with the multipath information of the wireless link, otherwise enters step A4;

A4 repeats the steps A1, A2 and A3 until all wireless links in the wireless link set are polled;

The step B includes the following sub-steps:

The search window positions of the wireless links in the wireless link set are uniformly adjusted to the search window positions obtained according to the historical records.

The history information includes: location information of the effective path, wireless link information and signal-to-noise ratio corresponding to the effective path.

The recorded position information of the effective path includes the position of the first radius and the position of the last radius.

In the step A, if none of the wireless links in the wireless link set has an effective path, keep the search window positions of the wireless links in the wireless link set unchanged.

Through comparison, it can be found that the main difference between the technical solution of the present invention and the prior art is that, although each sector in the solution of the present invention performs independent polling processing as in the prior art, it is not independent in the processing of the polling results. , but the polling results are uniformly processed in the wireless link set, and the search window positions in the three sectors are uniformly adjusted, so that the search window positions of each wireless link in the wireless link set and the wireless link with the largest effective path SNR The search window positions are the same.

The difference in this technical solution has brought more obvious beneficial effects, that is, in the present invention, since the polling results are uniformly processed in the wireless link set, the search due to virtual paths and other reasons is avoided. The window is moved away from the normal position, thus ensuring that when the terminal moves, especially when moving between different sectors, it will not cause out-of-sync due to the above reasons and cause call drop, and realize the seamless connection of the mobile network, so that the network can be obtained Optimized and greatly improved call quality.

Description of drawings

Figure 1 is a schematic diagram of the transmission and reception of OTSR;

Fig. 2 is a schematic diagram of the search range of multipath search using polling technology;

Fig. 3 is a flow chart of performing polling search in a radio link set of a terminal according to a preferred embodiment of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings.

First, the basic principle of the present invention will be described. The method for enhanced search under the OTSR mode of the present invention performs unified processing on the polling search results in the wireless link set, comprehensively compares the polling results of the wireless link set, and finally obtains the maximum signal-to-noise ratio (Signal Noise Ratio, referred to as "SNR") ”), so that the position of the search window is uniformly determined in multiple sectors. Since the polling search results are uniformly processed in the wireless link set, the search window is only determined according to the multipath with the maximum SNR, and no virtual path is generated, so the call drop phenomenon when the terminal moves between different sectors can be avoided.

The process of polling and searching in a radio link set of a terminal according to a preferred embodiment of the present invention is shown in FIG. 3 .

First enter step 110, and poll a wireless link in the wireless link set. Wherein, the wireless link is one of the wireless link set corresponding to the terminal, and the polling process is completely the same as that of the prior art.

Then enter step 120, judge whether to find effective path, if yes then enter step 130, otherwise enter step 160. Wherein, the criteria for judging whether there is an effective diameter are well known in the art, and will not be described in detail here.

In step 130, it is judged whether the wireless link is the first wireless link in the wireless link set to poll for an effective path, if yes, go to step 150, otherwise go to step 140. In this step, it can be judged whether it is the first wireless link polled for a valid path by checking whether the history record of the wireless link set is empty, if the history record is empty, it is, otherwise it is not. Wherein, the history record includes information related to an effective path: effective path location information, radio link information and radio link SNR information.

In step 140, it is judged whether the SNR of the wireless link is greater than or equal to the historical SNR in the history record of the wireless link set, if yes, go to step 150, otherwise go to step 160. Wherein, the historical SNR is the SNR of the wireless link with the largest SNR polled before.

In step 150, the history record is updated to record that the effective path is a historical path, the wireless link is a historical wireless link, and the SNR of the wireless link is a historical SNR. The reason why the historical record is updated when the SNR of the wireless link is equal to the historical SNR is that the polling time of the wireless link is later than the historical record, and the wireless link in the historical record may change, so the wireless link polling time is later than the historical record. The valid paths that are inquired are more time-sensitive. It should be noted that when recording the historical path, record the positions of the head path and the end path.

In step 160, it is judged whether all wireless links in the wireless link set have been polled, and if so, proceed to step 170; otherwise, proceed to step 110 to continue polling the wireless links that have not yet been polled. In OTSR mode, a terminal may have three wireless links within the coverage of a base station.

In step 170, it is judged whether there is a valid polling result in the history record, if yes, enter step 180, otherwise end. This step is essentially to judge whether an effective path is found within the range of the three sectors covered by the base station. If there is an effective path, it must be the multipath of the wireless link with the largest SNR among all wireless links.

In step 180, all search windows in the wireless link set are uniformly adjusted to the search window positions obtained according to historical records. It should be noted that, in this step, the search windows of all wireless links in a wireless link set are adjusted to the same position.

It should be noted that, for the clarity of the process, the above process polls the wireless links in a wireless link set at a time. In actual processing, the polling of the wireless links in a wireless link set is performed independently in each In the sector, there is no order. Those skilled in the art can understand that this description is only for clarity of expression and does not affect the essence of the present invention.

Those skilled in the art can understand that the above method can also be used to perform a multipath search on all terminals within the coverage of the base station to determine the search window positions so as to determine the search window positions of all wireless links.

Although the present invention has been illustrated and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein, and without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (5)

1. the method for a reinforcing search under omnidirectional emission sector receiving mode is characterized in that, comprises following steps:

A carries out poll for each terminal respectively to each Radio Link in its Radio Link collection, obtains having in this Radio Link collection the Radio Link of effective diameter and signal to noise ratio maximum;

B is adjusted into the search window position unification of each Radio Link in the described Radio Link collection identical by the determined search window position of poll with the Radio Link of described signal to noise ratio maximum.

2. the method for reinforcing search under omnidirectional emission sector receiving mode according to claim 1 is characterized in that, described steps A comprises following substep:

Then enter steps A 2 as if the discovery effective diameter behind the described Radio Link in the described Radio Link collection of A1 poll, otherwise enter steps A 4;

A2 judges that whether this Radio Link is that first poll goes out to have the Radio Link of effective diameter in the described Radio Link collection, is historical information if then write down the multipath information of this Radio Link, otherwise enters steps A 3;

Whether A3 judges the signal to noise ratio of this Radio Link more than or equal to the signal to noise ratio in the described historical information, if then with the described historical information of multipath information updating of this Radio Link, otherwise enters steps A 4;

A4 repeating said steps A1, A2 and A3, all Radio Links in the intact described Radio Link collection of poll;

Comprise following substep among the described step B:

The search window position that obtains according to described historical record is adjusted in the search window position unification of each Radio Link in the described Radio Link collection.

3. the method for reinforcing search under omnidirectional emission sector receiving mode according to claim 2 is characterized in that, described historical information comprises: the positional information of described effective diameter, the wireless link information of described effective diameter correspondence and signal to noise ratio.

4. the method for reinforcing search under omnidirectional emission sector receiving mode according to claim 3 is characterized in that, the positional information of the described effective diameter of record comprises first path position and last path position.

5. the method for reinforcing search under omnidirectional emission sector receiving mode according to claim 1, it is characterized in that, in the described steps A, if have effective diameter without any a described Radio Link in the described Radio Link collection, then keep the search window position of the described Radio Link in this Radio Link collection constant.

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