[0033] In the embodiment of the present invention, in order to reduce the number of silent periods set when the cognitive (CR) system performs in-band sensing, and reduce the same-channel interference and adjacent-channel interference generated when the CR system performs out-of-band sensing, the CR system The base station divides at least one sub-area from its own coverage area according to preset conditions; and sets an execution period for each sub-area, and instructs the selected user terminal to sense the designated channel within the corresponding execution period.
[0034] When the base station in the CR system needs to perform in-band sensing on the current working channel and its adjacent channels (including N channel, N-1 channel and N+1 channel), the base station confirms that the The physical location of the user terminal, and attribute the user terminals with close physical locations to the same sub-area, then determine the number of user terminals contained in each sub-area, and determine the uniform set for each sub-area according to the smallest value in the number The number of silent periods, the unified silent period set is the execution period set for each sub-area when the base station performs in-band sensing, and the selected user terminals in each sub-area must perform a specific channel (N channel) and its adjacent channels (N-1 channel or/and N+1 channel) for sensing.
[0035] When the base station in the CR system needs to perform out-of-band sensing on the N+/-Δ channel (Δ>1), the base station first determines to work on the designated channel (N+/-Δ channel) and its adjacent channel (N+/- Δ+1 channel and N+/-Δ-1 channel) neighbor base stations (called interfering neighbor base stations), the base station divides the sub-areas overlapping with the coverage areas of each interfering neighbor base station in its own coverage area as interference sub-areas, And set the silent period of each interfering neighbor base station as the execution period of the corresponding sub-area, and divide the sub-area that does not overlap with the coverage area of each neighbor base station in its own coverage area into a non-interference sub-area, and set the preset perception effective time It is set as an execution period of the non-interference sub-area; in an execution period, the base station instructs all user terminals in the corresponding sub-area to sense the designated channel.
[0036] Preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.
[0037] Referring to FIG. 2A , in this embodiment, a cognitive (CR) system includes multiple base stations (BS) 20 and multiple user terminals 21 .
[0038] The base station 20 is used to divide at least one sub-area from its own coverage area according to preset conditions; and set an execution period for each sub-area, and instruct the selected user terminal 21 to sense the designated channel within the corresponding execution period;
[0039] The user terminal 21 is configured to sense the designated channel according to the scheduling of the base station 20 .
[0040]Referring to FIG. 2B , in this embodiment, the base station 20 includes a communication unit 200 , a first processing unit 201 , a second processing unit 202 and a third processing unit 203 .
[0041] The communication unit 200 is used to notify each user terminal 21 of the execution period set by the base station 20 in the form of broadcast, and instruct the selected user terminal 21 to sense the designated channel, and accept the sensing result returned by the user terminal 21 .
[0042] The first processing unit 201 is configured to divide at least one sub-area from the coverage area of the communication device according to preset conditions;
[0043] The second processing unit 202 is configured to set an execution period for each sub-region;
[0044] The third processing unit 203 is configured to select a user terminal in each sub-area to sense a designated channel within a corresponding execution period.
[0045] Based on the above system architecture, in this embodiment, base station 20A and base station 20B are neighbor base stations to each other, base station 20A and base station 20C are neighbor base stations to each other, the working channel occupied by base station 20A is called N channel, and the adjacent channels are called N channels respectively. -1 channel and N+1 channel, base station 20B works on N-1 channel, and base station 20C works on N+1 channel, obviously, both base station 20B and base station 20C are interfering neighbor base stations of base station 20A, base station 20B and base station The CR systems controlled by 20C are all interfering neighbor systems of the CR system controlled by base station 20A. Referring to FIG. 3A, in this embodiment, the detailed flow of the first case where the base station 20A performs in-band sensing is as follows:
[0046] Step S300: the base station 20A determines the physical location of each accessed user terminal 21 within its own coverage area.
[0047] Step S310: the base station 20A assigns the user terminals 21 with close physical locations to the same sub-area.
[0048] In practical applications, when user terminals 21 with close physical locations perform sensing operations, the sensing results obtained are relatively similar. Therefore, in this embodiment, the base station 20A assigns the user terminals 21 with close physical locations to the same sub-area, for example , the base station 20A assigns all user terminals 21 in a circular area divided by a radius ε with a certain coordinate point as the center to the same sub-area. When the user terminal 21 is a non-mobile terminal, as long as its physical location does not change, the sub-area it belongs to will not change; and when the user terminal 21 is a mobile terminal, the sub-area must be re-divided periodically, To determine the sub-area to which the user terminal 21 currently belongs.
[0049] Step S320: The base station 20A determines the number of user terminals 21 contained in each sub-area, and sets the smallest value among them as U.
[0050] In this embodiment, the base station 20 determines the number of unified silent periods set for each sub-area according to the relationship between U and the preset value K, where K represents at least the number of user terminals 21 required for effective sensing of a channel, K is an integer and K≥1.
[0051] Step S330: when 2K≦U<3K, the base station 20A sets two uniform quiet periods (quiet period) for each divided sub-area.
[0052] In this embodiment, when performing in-band sensing, the unified silent period set by the base station 20A is also the unified execution period of each sub-area, and the base station 20A notifies each user terminal 21 of the set silent period (execution period) in the form of broadcast, And in the silent period, the selected mobile terminals are scheduled to sense the designated channel and its adjacent channels.
[0053] Step S340: During the first silent period, the base station 20A coordinates its own silent period with that of the base station 20B to synchronize the silent period on the N-1 channel, N channel, N+1 channel and N+2 channel , and then, the base station 20A selects 2K user terminals 21 from each sub-area to perceive the N channel and the N+1 channel respectively, wherein, among the 2K user terminals 21 belonging to the same sub-area, each K user terminal 21 sense the same channel.
[0054] For example, when K=1, the base station 20A selects a user terminal 21 from each sub-area to sense the N channel, and simultaneously selects a user terminal 21 from each sub-area to sense the N+1 channel, that is, in the same sub-area Two user terminals are selected in the area to perceive the N channel and the N+1 channel respectively. Since U≥2K and K≥1, each sub-area contains at least two user terminals 21 .
[0055] Step S350: During the second silent period, the base station 20A coordinates its own silent period with that of the base station 20C to be synchronized, so that the silent periods on the N+1 channel, N channel, N-1 channel and N-2 channel also Synchronization is achieved, and then, the base station 20A selects 2K user terminals 21 from each sub-area to perceive the N channel and the N-1 channel respectively, wherein, among the 2K user terminals 21 belonging to the same sub-area, each K User terminal 21 perceives the same channel.
[0056] In the above case, the base station 20A has already completed the in-band sensing through the user terminals 21 in each sub-area by only setting the unified silent period twice. Compared with the prior art, the number of times of setting the unified silent period is reduced to a certain extent , shortening the total silent period time, thereby improving the service quality of the CR system. The user terminal 21 performing in-band sensing in each sub-area sends the obtained sensing results to the base station 20A, and the base station 20A obtains the chains of N channels, N-1 channels, and N+1 channels for different sub-areas by analyzing the received sensing results. road quality.
[0057] Of course, the base station 20A can also complete the sensing of the N channel and the N-1 channel in the first silent period through the above method, and complete the sensing of the N channel and the N+1 channel in the second silent period.
[0058] In addition, the base station 20A can also complete the sensing of the N channel and the N-1 channel in the first silent period through the above method, and complete the sensing of the N+1 channel in the second silent period, or complete the sensing of the N+1 channel in the first silent period. The sensing of the N channel and the N+1 channel is completed, and the sensing of the N-1 channel is completed in the second silent period.
[0059] It can be seen that the operations performed by the base station 20A in the first silent period and the second silent period can be replaced, and the number of channels perceived by the base station 20A in each silent period can be changed, which mainly depends on the impact on the interfering neighboring base stations, In general, the base station 20A will choose a scheme that causes fewer subordinate silent periods of interfering neighboring base stations.
[0060] Different from the above situation, when U≥3K, the base station 20 only needs to set a silent period once to complete the sensing of N channel, N−1 channel and N+1 channel. Referring to FIG. 3B , in this embodiment, the detailed flow of the second case where the base station 20A performs in-band sensing is as follows:
[0061] Step S3000: The base station 20A determines the physical location of each user terminal 21 that has been accessed within its own control area.
[0062] Step S3100: The base station 20A assigns the user terminals 21 with close physical locations to the same sub-area, and determines the number of user terminals 21 contained in each sub-area, and sets the smallest value among them as U.
[0063] Step S3200: When U≥3K, the base station 20A sets a uniform silent period (execution period) for each divided sub-area.
[0064] Step S3300: During the set silent period, the base station 20A coordinates its silent period with those of the base station 20B and the base station 20C to be synchronized, so that the silent periods on the N channel, N+/-1 channel and N+/-2 channel are synchronized.
[0065] Step S3400: The base station 20A selects 3K user terminals 21 from each sub-area to sense the N channel, N-1 channel, and N+1 channel respectively, wherein, among the 3K user terminals 21 belonging to the same sub-area, each K user terminals 21 perceive the same channel.
[0066] Since U≥3K and K≥1, each sub-area contains at least 3K user terminals 21 .
[0067] In the above two cases, when base station 20A selects user terminal 21 in each sub-area, it can be randomly selected or can be selected according to the conditions set. (N channel) and its adjacent channel (N-1 channel or/and N+1 channel) for sensing.
[0068] In this way, only one unified quiet period is set, and the base station 20A has completed in-band sensing through the user terminals 21 in each sub-area, and obtains the N channel, N-1 channel and N+ channel according to the sensing results returned by each user terminal 21 1 channel for link quality in different sub-areas. In this way, the number of unified quiet periods set by the base station 20A is further reduced, and the total quiet period time is shortened, thereby further improving the service quality of the CR system.
[0069] Different from the above two cases, in the third case, when U<2K, the base station 20A sets three unified silent periods, and selects K user terminals from each sub-area in each silent period for N channels, N -1 channel or N+1 channel for sensing. In this process, when the base station 20A determines that no interfering neighbor base station is working on the N-1 channel, the silent period used for sensing the N channel and the N+1 channel in the three set silent periods can be set as a continuous period of time, In this way, the base station 20A can instruct the corresponding user terminal 21 to sense the N channel during this time period, thereby reducing the time of the subordinate silent period set on the N+1 channel, thereby shortening the total silent period.
[0070] On the other hand, when base station 20A performs out-of-band detection on N+/-Δ (Δ>1) channels other than N channels, base station 20A needs to divide sub-areas according to the distribution of its own coverage area and the coverage area of neighboring interfering base stations, And respectively instruct all user terminals 21 in each sub-area to sense the N+/-Δ channel within the corresponding execution period. In the following, base station 20A needs to perform out-of-band sensing on N+Δ channels as an example. Referring to FIG. 4A , in the embodiment of the present invention, the detailed process of base station 20 performing out-of-band sensing is as follows:
[0071] Step 400: the base station 20A determines the interfering neighbor base stations working on the N+Δ channel, the N+Δ-1 channel and the N+Δ+1 channel.
[0072] In this embodiment, the neighbor base station 20B of the base station 20A works on the N+Δ channel, and the neighbor base station 20C works on the N+Δ+1 channel. According to the above situation, when the base station 20A instructs the user terminal 21 that has been accessed in its own coverage area to sense the N+Δ channel, the base station 20B will cause co-channel interference, and the base station 20C will cause adjacent-channel interference. Obviously, the base station 20B and Base station 20C is an interfering neighbor base station of base station 20A.
[0073] Step S410: The base station 20A divides sub-areas within its own coverage.
[0074] Referring to the oblique line in Figure 4B, the base station 20A sets the overlapping portion of its own coverage area and the base station 20B coverage area as the first strong interference area; referring to the horizontal line in Figure 4B, the base station 20A sets its own coverage area and the base station 20B The overlapping part of the coverage area of 20C is set as the second strong interference area; referring to the solid color part in FIG. 4B , the base station 20A sets only the part belonging to its own coverage area as the non-interference area.
[0075] Step S420: The base station 20A sets an execution period for each sub-area.
[0076]For the first strong interference zone, base station 20A sets the silent period of the CR system controlled by base station 20B as the execution period of the first strong interference zone; and for the second strong interference zone, base station 20A sets the silent period of the CR system controlled by base station 20C Set as the execution period of the second strongest interference zone.
[0077] For the non-interference zone, since the user terminal 21 therein is not in the overlapping area of the coverage areas of the two base stations 20, co-channel interference or adjacent-channel interference will not occur, therefore, the base station 20 sets the preset sensing effective time as the non-interference zone The execution period of , that is, the user terminal 21 in the non-interference zone can sense the N+Δ channel at any time within the effective sensing time. Generally, it senses the N+Δ channel when it is in an idle state.
[0078] In practical applications, if the coverage areas of the base station 20B and the base station 20C overlap, that is, the base station 20B and the base station 20C are neighbor base stations each other, then the silent periods of the base station 20B and the base station 20C can be coordinated to be synchronized. In this case, the above-mentioned The execution periods of the first strong interference area and the second strong interference area are the same.
[0079] Step S430: the base station 20A instructs all user terminals 21 in each sub-area to sense the N+Δ channel in the corresponding execution period, and returns the sensing result to the base station 20A.
[0080] Step S440: The base station 20A receives the sensing results returned by each user terminal 21 within the preset effective sensing time, comprehensively analyzes all the sensing results, and finally generates a unified sensing report.
[0081] In the above-mentioned embodiment, since the user terminals 21 in the first and second strong interference areas sense the N+Δ channel during the silent periods of the base station 20B and the base station 20C, co-channel interference and adjacent channel interference will not occur. interference phenomenon. In this way, the base station 20A obtains the link quality information of the N+Δ channel for each user terminal 21 in its own coverage area by avoiding co-channel interference and adjacent-channel interference through partitioning, thereby effectively improving the CR Perceived reliability of the system to authorized users, thereby reducing interference to authorized users.
[0082] Of course, if the neighbor base station 20B and the neighbor base station 20C of the base station 20A work on one or any two of the N+Δ channel, the N+Δ-1 channel, and the N+Δ+1 channel, and they are not neighbor base stations, Then the base station 20A can also complete the sensing of the N+Δ channel by avoiding co-channel interference and adjacent-channel interference through the above method, which will not be repeated here.
[0083] In addition, the user terminals 21 in the first and second strong interference areas can also request the base station 20B and the base station 20C to forward the sensing results of the N+Δ channel within the sensing effective time, and the same technical effect can also be achieved, and it is not necessary here Let me repeat.
[0084] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.
