A user grouping and power allocation method for PD-NOMA system

Abstract

The present invention discloses a method for user grouping and power allocation in a PD-NOMA system, the method comprising: obtaining the total number of users in the PD-NOMA system, the receiving end symbol signal-to-noise ratio corresponding to each user, and the grouping threshold parameter; obtaining a first group through a set grouping scheme according to the receiving end symbol signal-to-noise ratio and the grouping threshold parameter corresponding to each user; removing the users in the first group from the total number of users, and continuing to group the remaining users through the set grouping scheme until all users have completed grouping; determining the power allocation coefficient based on the obtained user grouping, and obtaining the channel capacity of each group and the power allocation of users in each group. A grouping scheme for multi-user scenarios in a PD-NOMA system, constraints for user devices to share the same spectrum resources in groups, a power allocation scheme for user devices sharing the same spectrum resources, and a decoding order scheme for the receiving end are provided.

Description

Technical Field

[0001] The present application belongs to the field of sixth-generation wireless communication technology, and relates to power domain non-orthogonal multiple access systems, multi-user grouping, uplink and downlink power allocation, and SIC decoding order, and in particular to a PD-NOMA system user grouping and power allocation method. Background Art

[0002] In traditional orthogonal multiple access (OMA), each device has dedicated wireless resources. In non-orthogonal multiple access (NOMA) systems, different users are allowed to share the same time-frequency resources for data transmission. Power domain non-orthogonal multiple access (PD-NOMA) is one of the NOMA solutions. It enables multiple devices to share the same spectrum resources in the power domain, that is, different devices are distinguished by having different power levels on the same resources.

[0003] In the PD-NOMA system, the signals of user devices sharing the same wireless resources overlap. The receiver must distinguish them based on the strength of the received signals. Successive interference cancellation (SIC) is usually used at the receiver to reduce the interference between different user signals. The receiver first decodes the signal with the highest received power, while other signals with lower power are considered interference. When the signal is successfully decoded, it is eliminated from the overlapping signals. After that, the signal with the strongest energy in the received signal is decoded again and removed. By decoding the strongest energy signals one by one and eliminating them from the received signal, the desired signal is finally decoded. Obviously, the power allocation scheme is crucial to the PD-NOMA system. It not only affects the SIC decoding order of the overlapping signals at the receiver, but also determines the overall system capacity performance that can be achieved by sharing resources. On the other hand, given the massive number of devices in mIoT, how to group them so that the required independent resource blocks are minimized to save spectrum resources, while ensuring the service quality of each device and improving the performance of the entire system is another difficult problem and hot spot worth studying in the PD-NOMA topic.

[0004] In the existing research on power allocation and user grouping of PD-NOMA systems, some literature only focuses on single issues such as user grouping schemes or power allocation schemes within a subchannel, without systematically considering user grouping and power allocation together, resulting in insufficient resource utilization. On the single issue of power allocation, existing literature either studies downlink subchannels or uplink subchannels, and most of them focus on a single subchannel. On the single issue of multi-user grouping, many literatures only include two user devices in a group, which fails to fully utilize spectrum resources to accommodate more users. A few literatures study the joint optimization scheme of user grouping and power control problems for uplink or downlink systems, and intend to improve the overall system performance by jointly controlling user grouping and power allocation. However, currently, there is no literature or patent system that provides a lightweight grouping solution for multi-user scenarios, constraints under which user devices can share the same spectrum resources in groups, an optimal power allocation solution for user devices sharing the same spectrum resources, and a decoding order solution at the receiving end for the three major constraints of given user quality of service requirements (i.e., minimum achievable transmission rate), total sub-channel transmit power, and SIC decoding constraints (i.e., the power difference between the signal to be decoded and interference and noise). Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a user grouping and power allocation method for a PD-NOMA system, a grouping scheme for multi-user scenarios under the PD-NOMA system, constraints under which user devices can share the same spectrum resources in groups, a power allocation scheme for user devices sharing the same spectrum resources, and a decoding order scheme for the receiving end.

[0006] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0007] In a first aspect, the present invention provides a method for user grouping and power allocation in a PD-NOMA system, comprising:

[0008] Obtain the total number of users in the PD-NOMA system, the receiving end symbol signal-to-noise ratio corresponding to each user, and the grouping threshold parameters;

[0009] According to the receiving end symbol signal-to-noise ratio and the grouping threshold parameter corresponding to each user, a first group is obtained through a set grouping scheme;

[0010] The users in the first group are removed from the total number of users, and the remaining users are grouped according to the set grouping scheme until all users are grouped;

[0011] Based on the obtained user grouping, the power allocation scheme for each group of users and the SIC decoding order at the receiving end are confirmed.

[0012] Furthermore, the grouping scheme includes:

[0013] Set up PD-NOMA system There are ungrouped users, and the symbol signal-to-noise ratio at the user receiving end is: , and satisfies ;

[0014] in, For the The symbol signal-to-noise ratio of the user receiving end is For base stations and users The channel gain between is the variance of the complex Gaussian white noise at the receiving end, is the total transmit power on a resource block;

[0015] The grouping threshold parameters are:

[0016] ;

[0017] in, is the grouping threshold parameter, is the channel bandwidth of a resource block, The minimum quality of service (i.e., minimum achievable rate) required for each user equipment on its resource block, The minimum difference between the power of the signal to be decoded at the receiving end and the power of the interference signal and the noise power;

[0018] According to the signal-to-noise ratio of the receiving end symbol corresponding to each user and group threshold parameters , get the maximum number of users in the current group through the set grouping constraints;

[0019] The users in the current group are replaced and updated by the set group user replacement method to obtain an updated group.

[0020] Furthermore, the receiving end symbol signal-to-noise ratio corresponding to each user and group threshold parameters , the maximum number of users in the current group is obtained by setting grouping constraints, including:

[0021] Select the user with the smallest signal-to-noise ratio at the receiving end among all the users that are not currently grouped. First, determine how many elements can be combined with In a group, get the maximum number of users in the current group.

[0022] Furthermore, the group user replacement method comprises:

[0023] Under the condition that the maximum number of users in the current group remains unchanged, the maximum receiving end symbol signal-to-noise ratio in the current group is eliminated one by one, and under the condition that the set grouping constraints are met, the The smaller receiving end symbol signal-to-noise ratio is replaced.

[0024] Furthermore, the grouping constraint condition is:

[0025] ;

[0026] in, is the number of users in a group, For a group of Users, For the The symbol signal-to-noise ratio of the user receiving end is , is the grouping threshold parameter.

[0027] Furthermore, the determining of the power allocation coefficient based on the obtained user grouping to obtain the channel capacity of each group and the power allocation of users in each group includes:

[0028] In the downlink PD-NOMA system, after the downlink users are grouped, the power allocation coefficient is determined for each group of downlink users to obtain the downlink power allocation scheme and the decoding order of the downlink user receiving end;

[0029] In the uplink PD-NOMA system, after the uplink users are grouped, the power allocation coefficient is determined for each group of uplink users to obtain the uplink power allocation scheme and the decoding order at the base station receiving end.

[0030] Furthermore, in the downlink PD-NOMA system, after the downlink users are grouped, a power allocation coefficient is determined for each group of downlink users to obtain a downlink power allocation scheme and a decoding order of the downlink user receiving end, including:

[0031] Confirm the power allocation coefficient for downlink users , the expression is:

[0032] ;

[0033] in, The channel bandwidth is The total number of downlink users in a downlink resource block is For the Users and , For the The receiving end symbol signal-to-noise ratio of the user satisfies , is the total transmit power of the base station in a downlink resource block;

[0034] Based on the power allocation coefficient of the downlink user, the base station sends the signal to the user. The transmitted signal power for:

[0035] ;

[0036] The total channel capacity of a group of downlink users is obtained as:

[0037] ;

[0038] user After receiving the signal, SIC decoding is used. The SIC decoding order is: D j down = [ 1 , 2 , ⋯ , j − 1 , j ] ,user The received signal is decoded in the order of users from far to near, from the user farthest from the base station to the user closest to the base station; the signal sent by the base station to user 1 is decoded first, and the decoded signal sent to user 1 is removed from the received signal, and then the signal sent by the base station to user 2 is decoded and removed, until the decoded signal sent by the base station to user The signal itself.

[0039] Furthermore, in the uplink PD-NOMA system, after the uplink users are grouped, a power allocation coefficient is determined for each group of uplink users to obtain an uplink power allocation scheme and a decoding order of a base station receiving end, including:

[0040] Confirm the power allocation coefficient for uplink users , the expression is:

[0041] ;

[0042] in, The channel bandwidth is The total number of uplink users in a resource block is For the Users and , For the The receiving end symbol signal-to-noise ratio of the user satisfies , is the total transmit power that can be carried by an uplink resource block;

[0043] Based on the power allocation coefficient of the uplink user, the base station sends the signal to the uplink user. The transmitted signal power for:

[0044] ;

[0045] The total channel capacity of a group of uplink users is obtained as:

[0046] ;

[0047] The base station receiver uses SIC decoding after receiving the signal. The SIC decoding order is: D up = [ M up , M up − 1 , ⋯ , 2 , 1 ] The base station receiving end starts decoding in the order of users from near to far, from the user closest to the base station to the user farthest from the base station; first decode the user from the user The signal from the user is decoded After removing the signal from the received signal, the decoder and removes it until the signal from user 1 is decoded.

[0048] In a second aspect, the present invention provides a computer device, including a processor and a storage medium;

[0049] The storage medium is used to store instructions;

[0050] The processor is used to operate according to the instructions to execute the steps of the method described in the first aspect.

[0051] In a third aspect, the present invention provides a computer storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the method described in the first aspect.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] The present invention provides a multi-user grouping design scheme in a PD-NOMA system, an uplink and downlink power allocation scheme for each group, and a SIC decoding order design scheme. The grouping design scheme can ensure that the number of users in each group is maximized, thereby minimizing the total number of groups, that is, minimizing the number of required resource blocks (or subchannels), saving the spectrum resources required in the mIoT scenario, and improving spectrum efficiency. In addition, the grouping design scheme can maximize the overall system capacity of all users and ensure that each user meets the minimum service quality (that is, the minimum channel capacity) requirements. In the present invention, the downlink SIC decoding is performed in the order of users from far to near, while the uplink SIC decoding is performed in the order of users from near to far. The intra-group power allocation scheme and the SIC decoding order design scheme in the present invention can ensure that the channel capacity on each resource block (or subchannel) is maximized. The user grouping scheme, intra-group power allocation scheme, and SIC decoding order design scheme designed by the present invention can well save spectrum resources and improve spectrum efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 The figure is a schematic diagram of the process of a method for grouping users in a PD-NOMA system provided by an embodiment of the present invention;

[0055] Figure 2 FIG. 2 is a schematic diagram of a downlink PD-NOMA system decoding solution provided by an embodiment of the present invention;

[0056] Figure 3 FIG. 1 is a schematic diagram of an uplink PD-NOMA system decoding solution provided by an embodiment of the present invention;

[0057] Figure 4 The figure shows a schematic diagram of a curve showing a change in system capacity with the number of users in a PD-NOMA system and an OMA system in a sub-channel provided by an embodiment of the present invention;

[0058] Figure 5 The figure is a schematic diagram of a curve showing a change in the number of groups versus the number of users in a PD-NOMA system provided by an embodiment of the present invention;

[0059] Figure 6 The figure is a schematic diagram of a curve showing how the average channel capacity of each sub-channel of a PD-NOMA system provided in an embodiment of the present invention changes with the number of users. DETAILED DESCRIPTION

[0060] The technical concept of the present invention is: obtaining the total number of users of the PD-NOMA system, the receiving end symbol signal-to-noise ratio and grouping threshold parameters corresponding to each user; obtaining the first group through the set grouping scheme according to the receiving end symbol signal-to-noise ratio and grouping threshold parameters corresponding to each user; removing the users in the first group from the total number of users, and continuing to group based on the remaining users through the set grouping scheme until all users have completed grouping; determining the power allocation coefficient based on the obtained user grouping, and obtaining the channel capacity of each group and the power allocation of users in each group. Provide a grouping scheme for multi-user scenarios under the PD-NOMA system, constraints for user devices to share the same spectrum resources in groups, a power allocation scheme for user devices sharing the same spectrum resources, and a decoding order scheme for the receiving end.

[0061] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present application and its application or use.

[0062] Example 1

[0063] This embodiment provides a PD-NOMA system user grouping and power allocation method, including:

[0064] Obtain the total number of users in the PD-NOMA system, the receiving end symbol signal-to-noise ratio corresponding to each user, and the grouping threshold parameters;

[0065] According to the receiving end symbol signal-to-noise ratio and the grouping threshold parameter corresponding to each user, a first group is obtained through a set grouping scheme;

[0066] The users in the first group are removed from the total number of users, and the remaining users are grouped according to the set grouping scheme until all users are grouped;

[0067] Based on the obtained user grouping, the power allocation scheme for each group of users and the SIC decoding order at the receiving end are confirmed.

[0068] The grouping scheme includes:

[0069] Set up PD-NOMA system There are ungrouped users, and the symbol signal-to-noise ratio at the user receiving end is: , and satisfies ;

[0070] in, For the The symbol signal-to-noise ratio of the user receiving end is For base stations and users The channel gain between is the variance of the complex Gaussian white noise at the receiving end, is the total transmit power on a resource block;

[0071] The grouping threshold parameters are:

[0072] ;

[0073] in, is the grouping threshold parameter, is the channel bandwidth of a resource block, The minimum quality of service (i.e., minimum achievable rate) required for each user equipment on its resource block, The minimum difference between the power of the signal to be decoded at the receiving end and the power of the interference signal and the noise power;

[0074] According to the signal-to-noise ratio of the receiving end symbol corresponding to each user and group threshold parameters , get the maximum number of users in the current group through the set grouping constraints;

[0075] The users in the current group are replaced and updated by the set group user replacement method to obtain an updated group.

[0076] According to the receiving end symbol signal-to-noise ratio corresponding to each user and group threshold parameters , the maximum number of users in the current group is obtained by setting grouping constraints, including:

[0077] Select the user with the smallest signal-to-noise ratio at the receiving end among all the users that are not currently grouped. First, determine how many elements can be combined with In a group, get the maximum number of users in the current group.

[0078] The group user replacement method comprises:

[0079] Under the condition that the maximum number of users in the current group remains unchanged, the maximum receiving end symbol signal-to-noise ratio in the current group is eliminated one by one, and under the condition that the set grouping constraints are met, the The smaller receiving end symbol signal-to-noise ratio is replaced.

[0080] The grouping constraints are:

[0081] ;

[0082] in, is the number of users in a group, For a group of Users, For the The symbol signal-to-noise ratio of the user receiving end is , is the grouping threshold parameter.

[0083] The method of determining the power allocation coefficient based on the obtained user grouping, and obtaining the channel capacity of each group and the power allocation of users in each group, comprises:

[0084] In the downlink PD-NOMA system, after the downlink users are grouped, the power allocation coefficient is determined for each group of downlink users to obtain the downlink power allocation scheme and the decoding order of the downlink user receiving end;

[0085] In the uplink PD-NOMA system, after the uplink users are grouped, the power allocation coefficient is determined for each group of uplink users to obtain the uplink power allocation scheme and the decoding order at the base station receiving end.

[0086] In the downlink PD-NOMA system, after the downlink users are grouped, a power allocation coefficient is determined for each group of downlink users to obtain a downlink power allocation scheme and a decoding order of the downlink user receiving end, including:

[0087] Confirm the power allocation coefficient for downlink users , the expression is:

[0088] ;

[0089] in, The channel bandwidth is The total number of downlink users in a downlink resource block is For the Users and , For the The receiving end symbol signal-to-noise ratio of the user satisfies , is the total transmit power of the base station in a downlink resource block;

[0090] Based on the power allocation coefficient of the downlink user, the base station sends the signal to the user. The transmitted signal power for:

[0091] ;

[0092] The total channel capacity of a group of downlink users is obtained as:

[0093] ;

[0094] user After receiving the signal, SIC decoding is used. The SIC decoding order is: D j down = [ 1 , 2 , ⋯ , j − 1 , j ] ,user The received signal is decoded in the order of users from far to near, from the user farthest from the base station to the user closest to the base station; the signal sent by the base station to user 1 is decoded first, and the decoded signal sent to user 1 is removed from the received signal, and then the signal sent by the base station to user 2 is decoded and removed, until the decoded signal sent by the base station to user The signal itself.

[0095] In the uplink PD-NOMA system, after the uplink users are grouped, a power allocation coefficient is determined for each group of uplink users to obtain an uplink power allocation scheme and a decoding order of a base station receiving end, including:

[0096] Confirm the power allocation coefficient for uplink users , the expression is:

[0097] ;

[0098] in, The channel bandwidth is The total number of uplink users in a resource block is For the Users and , For the The receiving end symbol signal-to-noise ratio of the user satisfies , is the total transmit power that can be carried by an uplink resource block;

[0099] Based on the power allocation coefficient of the uplink user, the base station sends the signal to the uplink user. The transmitted signal power for:

[0100] ;

[0101] The total channel capacity of a group of uplink users is obtained as:

[0102] ;

[0103] The base station receiver uses SIC decoding after receiving the signal. The SIC decoding order is: D up = [ M up , M up − 1 , ⋯ , 2 , 1 ] The base station receiving end starts decoding in the order of users from near to far, from the user closest to the base station to the user farthest from the base station; first decode the user from the user The signal from the user is decoded After removing the signal from the received signal, the decoder and removes it until the signal from user 1 is decoded.

[0104] The following example is used to illustrate the PD-NOMA system user grouping and power allocation method of this embodiment.

[0105] Assume that there are N users in the entire PD-NOMA system, and the received symbol SNR is ,and . is the symbol SNR of the jth user receiver, where is the channel gain between the base station and device j, is the variance of the complex Gaussian white noise at the receiving end, is the total power on a resource block (or a subchannel). For the downlink PD-NOMA system, is the total transmit power of the base station on a downlink resource block (or a subchannel). For the uplink PD-NOMA system, is the total transmit power that an uplink resource block (or a subchannel) can carry. Assume that the channel bandwidth of a resource block (or a subchannel) is , the minimum service quality (or channel capacity) requirement for each user equipment on its resource block is , the minimum difference between the power of the signal to be decoded at the receiving end and the power of the interference signal and the noise power is . Calculate the grouping threshold parameter .

[0106] The user grouping solution of the PD-NOMA system provided in this embodiment is designed as follows:

[0107] Assume that there are M users in a group, and their receiving end symbol SNR satisfies To maximize the channel capacity of the group, the SNR of users in a group should satisfy the grouping constraint In the grouping scheme given in this embodiment, we first start from The smallest element in Let's analyze how many users can communicate with Assign them to the same group to maximize the number of users in the first group. Then, Start with the largest gain and see how many elements can be combined with In a group. In this way, we determine the maximum number of users in the group Once the maximum number of users is determined, try adjusting the users in the group to ensure that the number of users in the group If the value remains unchanged, try to keep the larger SNR in the group and use , thereby replacing the smaller SNR in The purpose of retaining these large SNRs is, on the one hand, to help the subsequent grouping to expand the number of users in the group, and on the other hand, to improve the channel capacity of the entire system. When the elements of the group are finally determined after multiple updates, they are removed from Next, we will continue to study the updated The smallest element in Which elements can be grouped with. Is an empty set.

[0108] The design can be seen in Figure 1 , including the following processing steps:

[0109] S1. Initialize the current grouping number parameters for , initialize the intermediate variables for .

[0110] S2. Calculate the current The total number of elements in the collection .from The first (and smallest) element in , and start analyzing the elements that can be grouped with it. As a collection The first element in . Define intermediate variables Used to count and The number of elements in the group, initialized for .if , jump to step S3; if , jump to step S8.

[0111] S3, when When , go to step S4. When After Elements and to form a group .if In elements can satisfy the condition ,but , go to step S3; if the condition is not met, that is, ,but , go to step S4.

[0112] S4. and After elements into a group. ,but The final grouping is , jump to step S8. , The initial group is , and determine whether to update or replace the group array based on the number of elements in the group at this time. , that is , jump to step S8; otherwise, that is, , let the variable , jump to step S5.

[0113] S5. When the variable When it is equal to 1, jump to step S8. Otherwise, When trying to use The smaller element in replaces the one in group This element. First, find the element exist The position in (indicated by the variable index), that is, . Include all possible replacement elements in the set middle, , The number of elements in . Define intermediate variables Used for statistics The number of elements that are ultimately replaced in for . Initialize intermediate variables for . Jump to step S6.

[0114] S6. When When , go to step S7. When After elements are used to replace and form a set . For the collection The elements in are reordered from smallest to largest, that is . The total number of elements in the variable Indicates that .if In this Elements satisfy the condition ,but , go to step S6; if the condition is not met, that is, ,but , go to step S7.

[0115] S7, if ,but , go to step S5. Otherwise, , for . For the collection The elements in are reordered from smallest to largest, that is If the set The number of elements in the set is less than The number of elements in , go to step S5; otherwise, that is, the set The number of elements in the set is equal to The number of elements in the set Replace the elements in the collection The elements in , , jump to step S5.

[0116] S8. Grouping parameters Updated to . Updated The grouping element of a group is The elements in , store them in The OK, that is .Will The elements in the set Deleted from Updated to If the updated collection If it is not an empty set, initialize the variable for , jump to step S2; otherwise, the grouping is completed and the final number of groups is output And the storage grouping .

[0117] After the users are grouped, a power allocation scheme and a decoding order at the user receiving end need to be determined for each group of users. The power allocation scheme has been described in detail and will not be repeated here.

[0118] In the downlink PD-NOMA system, assuming that a resource block or a subchannel with a channel bandwidth of B can accommodate Downlink users, The symbol SNR at the receiving end of each user is ,satisfy . It is the total transmit power of the base station in a downlink resource block (or a subchannel). Definition Base station to user The transmission power when sending a signal, is the power coefficient, then, Right now The signal sent by the base station can be expressed as ,in is the symbol sent by the base station to user i ( ).

[0119] The decoding order of the downlink user receiving end is as follows: Figure 2 As shown, the user The SIC decoding order after receiving the signal is D j down = [ 1 , 2 , ⋯ , j − 1 , j ] , that is, user Decoding starts in the order of users from farthest to closest. Specifically, users First, receive the signal ( , ) to decode the signal sent by the base station to user 1 (the user farthest from the base station) , then receive the signal from Remove the signal sent to user 1 and get the signal Then from this signal (i.e. ) decodes the signal sent to user 2 , then from the signal Remove the decoded signal of user 2 from , get the signal . Then, from the signal Decode the signal sent to user 3 , then from the signal Remove the signal sent to user 3 , get the signal And so on, until the base station decodes and sends it to the user. The signal .

[0120] In the uplink PD-NOMA system, assuming that a resource block or a subchannel with a channel bandwidth of B can accommodate Uplink users, The symbol SNR of the user at the base station side is ,satisfy . It is the total transmit power that an uplink resource block (or a subchannel) can carry. Definition For users The transmission power, is the power coefficient, then, ,Right now The received signal at the base station side can be expressed as ,in , For users The symbol sent to the base station ( ).

[0121] The decoding order of the base station receiving end is as follows Figure 3 As shown, the SIC decoding order of the base station after receiving the signal is: D up = [ M up , M up − 1 , ⋯ , 2 , 1 ] , that is, the base station starts decoding in the order of users from near to far. Specifically, the base station first receives the signal ( ) to decode the user The signal sent by the user closest to the base station to the base station , then receive the signal from Remove user from signal, get signal Then from this signal (i.e. ) to decode the user Signal sent to base station , then from the signal Remove user from Signal sent , get the signal . Then, from the signal Decode the user Signal sent to base station , and then from the signal Remove user from Signal sent , get the signal And so on, until the base station decodes the signal sent by user 1 to .

[0122] Example 2

[0123] Based on Example 1, this embodiment provides an example to illustrate the PD-NOMA system user grouping and power allocation method of Example 1.

[0124] Assume that the total number of users in a PD-NOMA system is , threshold parameter The SNRs of the 8 randomly selected user receivers are in ascending order: η = [ 8, 14, 16, 23, 25, 26, 28, 30 ] .

[0125] First from Middle edge users (i.e. users farthest from the base station, with the smallest SNR) Analyze whether it can form a group with other users. We take maximizing the number of users in this group as the goal and determine the initial grouping. , ,and , so the first group can accommodate at most Users, the initial grouping of this group is Next, try to minimize the number of users in the group. The smaller SNRs replace these larger SNRs (such as , ), thereby retaining these larger SNRs to improve the overall channel capacity. Specifically, from the maximum channel gain Start trying alternatives. That is, Disharmony In the case of grouping, are there two other smaller SNRs that can be combined with There are 3 user groups. , satisfying the constraints. Therefore, Instead, update the first group to . Similarly, try Can it be slightly smaller SNR , 25, 23 instead. Because , Gradually replaced by Next, try to replace The maximum SNR in If you use Replace, because at this time , cannot satisfy the grouping condition, so Need to be kept in the first group. Next, we analyze The second largest SNR Can it be replaced by a smaller SNR? , satisfying the grouping condition, In Can be replaced by The first group is finally updated to , save it to the first line of the final output G, that is G 1 = [ 8 , 14 , 23 ] . These grouped SNRs are Deleted, updated for η = [ 16, 25, 26, 28, 30 ] . Now follow the above process and select the current The smallest element in As the first element in the second group, we study the grouping scheme of this group. After iteration, we know that these 8 users are finally divided into Group, the grouping scheme is G = [ 8 , 14 , 23 ; 16 , 25 , 26 ; 28 , 30 ] In this embodiment, Each user ultimately requires 3 resource blocks.

[0126] The following is a power allocation scheme for each group. For the downlink PD-NOMA system, according to the power allocation scheme of Example 1, the first group can be obtained: G 1 = [ 8 , 14 , 23 ] The power allocation coefficients corresponding to the three users are , , The channel capacity of this group is kpbs. Group 2 G 2 = [ 16 , 25 , 26 ] The power allocation coefficients corresponding to the three users are , , The channel capacity of this group is kpbs. Group 3 G 3 = [ 28 , 30 ] The power allocation coefficients corresponding to the three users are , The channel capacity of this group is kpbs. Total system capacity When the jth user in each group performs SIC decoding, D j down = [ 1 , 2 , ⋯ , j − 1 , j ] Decode in order.

[0127] For the uplink PD-NOMA system, according to the power allocation scheme of Example 1, the first group can be obtained: G 1 = [ 8 , 14 , 23 ] The power allocation coefficients corresponding to the three users are , , The channel capacity of this group is kpbs. Group 2 G 2 = [ 16 , 25 , 26 ] The power allocation coefficients corresponding to the three users are , , The channel capacity of this group is kpbs. Group 3 G 3 = [ 28 , 30 ] The power allocation coefficients corresponding to the three users are , The channel capacity of this group is kpbs. Total system capacity When the base station decodes each group of users (assuming that the group contains M users), it follows D up = [ M , M − 1 , ⋯ , 2 , 1 ] Decode in order.

[0128] Example 3

[0129] Based on Example 1, this example compares the total channel capacity of M users on a subchannel of the PD-NOMA system with the average capacity of each channel when these users adopt the OMA mechanism.

[0130] The M users on a subchannel all meet the constraints required by the PD-NOMA system. Assume that the receiving SNR of M users is ( ϕ , η max ] The specific parameters are shown in the simulation parameters in Table 1.

[0131]

[0132] Table 1

[0133] Figure 4The system capacity of the PD-NOMA system on a subchannel is given The average channel capacity of M users in the OMA system The graph changes with the number of users. Figure 4 It can be seen from the figure that under the given parameter configuration, the channel capacity of the NOMA system on a subchannel is always better than the average channel capacity of the OMA system on a subchannel. When increasing, and The performance of both has been improved.

[0134] Example 4

[0135] Based on Example 1, this embodiment provides a simulation experiment example to illustrate the PD-NOMA system user grouping and power allocation method of Example 1.

[0136] The grouping scheme and intra-group power allocation scheme proposed in Example 1 were used in the simulation. Figure 5 and Figure 6 The number of groups and the average channel capacity of each subchannel when there are N users in the PD-NOMA system are given. For comparison, the figure also shows the average channel capacity of each subchannel in the OMA system. . Each time a random simulation is performed, The SNR of the user receiving end is ( ϕ , η max ] The specific parameters are shown in Table 1. In a simulation, the NOMA system and the OMA system use the same SNR data of the N users at the receiving end.

[0137] from Figure 5 It can be seen that in the case of the same number of users in the PD-NOMA system, the number of groups of users is It follows That is, when the user channel gain is good, the number of sub-channels that the PD-NOMA system needs to occupy will also decrease. Figure 5 As shown, when dB, Users have occupied sub-channels, which is much smaller than the 30 sub-channels required by the OMA system, saving 86.7% of channel resources. When it is large, the PD-NOMA system can greatly improve the spectrum efficiency and reduce the required channel resources, thereby meeting the needs of large-scale IoT scenarios with massive devices. Figure 6 It can be seen that when the number of users is the same, along with And, in the configuration in the figure, when When the channel capacity of each subchannel in the PD-NOMA system is the same, Both are greater than the average channel capacity of each subchannel in the OMA system .

[0138] Example 5

[0139] This embodiment provides a computer device, including a processor and a storage medium;

[0140] The storage medium is used to store instructions;

[0141] The processor is used to operate according to the instructions to execute the steps of the method described in Example 1.

[0142] Example 6

[0143] This embodiment provides a computer storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the method described in Embodiment 1 are implemented.

[0144] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0145] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0146] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1A function specified in one or more boxes.

[0147] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0148] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for user grouping and power allocation in a PD-NOMA system, characterized in that: include: Obtain the total number of users in the PD-NOMA system, the receiving end symbol signal-to-noise ratio corresponding to each user, and the grouping threshold parameters; According to the receiving end symbol signal-to-noise ratio and the grouping threshold parameter corresponding to each user, a first group is obtained through a set grouping scheme; The users in the first group are removed from the total number of users, and the remaining users are grouped according to the set grouping scheme until all users are grouped; Based on the obtained user grouping, determine the power allocation scheme for each group of users and the SIC decoding order at the receiving end; The grouping scheme includes: Set up PD-NOMA system There are ungrouped users, and the symbol signal-to-noise ratio at the user receiving end is: , and satisfies ; in, For the The symbol signal-to-noise ratio of the user receiving end is For base stations and users The channel gain between is the variance of the complex Gaussian white noise at the receiving end, is the total transmit power on a resource block; The grouping threshold parameters are: ； in, is the grouping threshold parameter, is the channel bandwidth of a resource block, is the minimum quality of service requirement for each user equipment on the corresponding resource block, The minimum difference between the power of the signal to be decoded at the receiving end and the power of the interference signal and the noise power; According to the signal-to-noise ratio of the receiving end symbol corresponding to each user and group threshold parameters , get the maximum number of users in the current group through the set grouping constraints; The users in the current group are replaced and updated by the set group user replacement method to obtain an updated group; The grouping constraints are: ； in, is the number of users in a group, For a group of Users, For the The symbol signal-to-noise ratio of the user receiving end is ; The group user replacement method comprises: Under the condition that the maximum number of users in the current group remains unchanged, the largest receiving end symbol signal-to-noise ratio in the current group is eliminated one by one, and under the condition that the set grouping constraints are met, the users are eliminated from Select a receiving end symbol signal-to-noise ratio smaller than the largest receiving end symbol signal-to-noise ratio in the current group for replacement; The method of determining the power allocation coefficient based on the obtained user grouping, and obtaining the channel capacity of each group and the power allocation of users in each group, comprises: In the downlink PD-NOMA system, after the downlink users are grouped, the power allocation coefficient is determined for each group of downlink users to obtain the downlink power allocation scheme and the decoding order of the downlink user receiving end; The downlink user receiving end starts decoding in the order of users from far to near, wherein the order from far to near is from the user farthest from the base station to the user closest to the base station; In the uplink PD-NOMA system, after the uplink users are grouped, the power allocation coefficient is determined for each group of uplink users to obtain the uplink power allocation scheme and the decoding order of the base station receiving end; The base station receiving end starts decoding in the order of users from near to far, where the order is from the user closest to the base station to the user farthest from the base station.

2. The PD-NOMA system user grouping and power allocation method according to claim 1, characterized in that: According to the receiving end symbol signal-to-noise ratio corresponding to each user and group threshold parameters , the maximum number of users in the current group is obtained by setting grouping constraints, including: Select the user with the smallest signal-to-noise ratio at the receiving end among all the users that are not currently grouped. First, determine how many users can be connected to the group while satisfying the set group constraints. In a group, get the maximum number of users in the current group.

3. The PD-NOMA system user grouping and power allocation method according to claim 1, characterized in that: In the downlink PD-NOMA system, after the downlink users are grouped, a power allocation coefficient is determined for each group of downlink users to obtain a downlink power allocation scheme and a decoding order of the downlink user receiving end, including: Confirm the power allocation coefficient for downlink users , the expression is: ； in, The channel bandwidth is The total number of downlink users in a downlink resource block is For the Users and , For the The receiving end symbol signal-to-noise ratio of the user satisfies , is the total transmit power of the base station in a downlink resource block; Based on the power allocation coefficient of the downlink user, the base station sends the signal to the user. The transmitted signal power for: ； The total channel capacity of a group of downlink users is obtained as: ； user After receiving the signal, SIC decoding is used. The SIC decoding order is: ,user The received signal is decoded in the order of users from far to near, from the user farthest from the base station to the user closest to the base station; first, the signal sent by the base station to user 1 is decoded, and the decoded signal sent to user 1 is removed from the received signal, and then the signal sent by the base station to user 2 is decoded and the signal sent to user 2 is removed, until the decoded signal sent by the base station to user The signal itself.

4. The PD-NOMA system user grouping and power allocation method according to claim 1, characterized in that: In the uplink PD-NOMA system, after the uplink users are grouped, a power allocation coefficient is determined for each group of uplink users to obtain an uplink power allocation scheme and a decoding order of a base station receiving end, including: Confirm the power allocation coefficient for uplink users , the expression is: ； in, The channel bandwidth is The total number of uplink users in a resource block is For the Users and , For the The receiving end symbol signal-to-noise ratio of the user satisfies , is the total transmit power that can be carried by an uplink resource block; Based on the power allocation coefficient of the uplink user, the base station sends the signal to the uplink user. The transmitted signal power for: ； The total channel capacity of a group of uplink users is obtained as: ； The base station receiver uses SIC decoding after receiving the signal. The SIC decoding order is: The base station receiving end starts decoding in the order of users from near to far, from the user closest to the base station to the user farthest from the base station; first decode the user from the user The signal from the user is decoded After removing the signal from the received signal, the decoder The signal will come from the user The signal from user 1 is removed until the signal from user 1 is decoded.

5. A computer device, characterized in that: including processor and storage medium; The storage medium is used to store instructions; The processor is configured to operate according to the instructions to execute the steps of the method according to any one of claims 1 to 4.

6. A computer storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 4 are implemented.

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