CN110324844B - Secondary user strong excitation power distribution method based on cooperative NOMA and cooperative spectrum sharing - Google Patents
Secondary user strong excitation power distribution method based on cooperative NOMA and cooperative spectrum sharing Download PDFInfo
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Abstract
本发明涉及一种基于合作NOMA与协作频谱共享的次要用户强激励功率分配方法，本发明通过优化次要用户NOMA传输的功率分配因子，使作为中继的SU传输速率达到最大。不仅可以有效提高主用户PU和次要用户SU的总速率，提高系统的频谱效率，而且可以同时激励更多的次要用户SU来作为主用户PU的转发中继，解决主用户PU和次要用户SU之间用户利益矛盾问题。
The invention relates to a secondary user strong excitation power allocation method based on cooperative NOMA and cooperative spectrum sharing. The present invention maximizes the SU transmission rate as a relay by optimizing the power allocation factor of secondary user NOMA transmission. Not only can it effectively increase the total rate of the primary user PU and the secondary user SU, and improve the spectral efficiency of the system, but also stimulate more secondary user SUs to act as the forwarding relay of the primary user PU, solving the problem of the primary user PU and the secondary user SU. The problem of conflicting user interests between user SUs.
Description
Technical Field
The invention relates to a secondary user strong excitation power distribution method based on cooperative NOMA (non-orthogonal multiple access technology) and cooperative spectrum sharing, belonging to the technical field of communication systems.
Background
With the emergence of 5G, the number of mobile devices is increased sharply, and the demand of user access is increased exponentially, but now spectrum resources are in short supply, so the scarcity of spectrum resources and the demand of users for increasing speed are a pair of main contradictions in the policy design of communication systems at present.
Cooperative spectrum sharing technology is a promising approach to the problem of spectrum scarcity in wireless communications, and has attracted increasing research interest from the industry and academia. In the cooperative spectrum sharing system, a Secondary User (SU) having no spectrum access grant can obtain a certain spectrum access time by transmitting a signal of the Secondary User (SU) as a relay. Therefore, the frequency spectrum utilization rate of the whole communication system can be improved through cooperation between the PU and the SU.
In most existing work related to cooperative spectrum sharing techniques, Secondary Users (SUs) acting as relays during the cooperative phase are mostly operated in an orthogonal mode. That is, the Secondary User (SU) divides the allocated resources (time slot or frequency band resources) into two parts, one part for its own transmission and the other part dedicated to forwarding information from the Primary User (PU). As a result, a Secondary User (SU) cannot fully utilize a given spectrum or access time to meet his own needs.
To further improve the efficiency of spectrum sharing, non-orthogonal multiple access techniques (NOMA) were introduced. Non-orthogonal multiple access technology (NOMA) is considered one of the most attractive technologies for fifth generation mobile communications (5G), allowing users to share the same frequency spectrum or time slot at the same time. The basic idea of non-orthogonal multiple access (NOMA) is to use non-orthogonal transmission at the transmitting end, different users present different power differences at the receiving end, actively introduce interference information, and then utilize Successive Interference Cancellation (SIC) to achieve correct demodulation of different user information. And since successive interference cancellation is employed at the receiving end, NOMA is well suited for cooperative communication. Therefore, it is necessary to combine NOMA with cooperative spectrum sharing techniques in an appropriate way to better utilize spectrum resources.
On the other hand, another important issue in cooperative spectrum sharing technology is relay selection and power allocation. However, most of the existing work of adopting the cooperation theory to make and solve the relay selection or power allocation problem in the downlink NOMA system is to maximize the sum rate and throughput or minimize the interruption probability of the whole system through a certain optimization strategy, and the fairness of resource allocation among users is not fully considered, and the unique user requirements of a Secondary User (SU) and a Primary User (PU) are not considered, so that the waste of communication resources is caused. Considering different requirements of users under different scenes, the method has great research significance when communication resources are scarce and the quantity of the users is rapidly increased.
There are some studies on cooperative NOMA and cooperative spectrum sharing today, and there are also a few studies that consider behavior between users in conjunction with the relevant game theory. The principle of the NOMA technology is to perform non-orthogonal multiplexing on related communication resources of different users, and demodulate by using the SIC at a receiving end, so that more users can share the current communication resources, the spectrum efficiency of the whole system is improved, and a certain user behavior contradiction problem inevitably exists in resource allocation due to introduction of multiple users. The secondary users as relays are usually selfish, and the secondary users want to satisfy their own forwarding rate requirements as much as possible while performing information forwarding work for the primary users. Therefore, the primary user needs to make an incentive system to make more secondary users actively participate in the forwarding work, and simultaneously, the benefit of the primary user is not lost. The research on the aspect of user behavior problems is also a key point of future research of NOMA.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a secondary user strong excitation power distribution method based on a cooperative NOMA and cooperative spectrum sharing environment;
the invention researches the performance of a multi-user relay communication system in a cooperative NOMA environment. The invention mainly researches the problems of power optimization and relay selection in the system. By utilizing the NOMA technology, the invention effectively improves the total rate of the PU and the SU, designs a strong excitation system to solve the benefit contradiction between the SU and the PU, and provides a power distribution algorithm to maximize the transmission rate of the SU used as the relay on the basis of ensuring the basic transmission rate requirement of the PU.
Given that Channel State Information (CSI) is known, compared to the conventional NOMA static power allocation strategy, the present invention optimizes the power allocation factor and forward power of the secondary user in consideration of the channel condition of downlink transmission. And a minimum rate requirement threshold of main user transmission is set to ensure that the performance of the PU as a frequency spectrum resource provider obtained by cooperation is better than that of a direct transmission condition. The rate of SU transmission as a relay is maximized by optimizing the power allocation factor for the secondary user NOMA transmission. The method can effectively improve the total rate of the PU and the SU and improve the spectrum efficiency of the system, and can simultaneously stimulate more SUs to be used as the forwarding relays of the PU, thereby solving the problem of the contradiction between the user benefits between the PU and the SU.
The technical scheme of the invention is as follows:
a secondary user strong excitation power distribution method based on cooperation NOMA and cooperation spectrum sharing is operated in a multi-user relay communication system based on cooperation NOMA, the multi-user relay communication system based on cooperation NOMA comprises a primary user system and a secondary user system, the primary user system refers to a primary user PU, the primary user PU comprises a primary transmitter PT and a primary receiver PR, the secondary user system comprises K secondary users SU, each secondary user SU comprises a transmitter and a receiver, and a transmitter-receiver pair is formed and is represented as STk-SRkThe master user PU is always in a communication state;
the primary user PU has access to bandwidth, but the channel conditions for direct transmission between the PT and PR are poor. On the other hand, each SU wants to get spectrum access time to transmit its own signal. But the primary user PU controls the allocation of access bandwidth. Therefore, the SU must assist the PU in forwarding in order to have an opportunity to send its own signal. To make better use of bandwidth resources, a cooperative transmission strategy is used, comprising two transmission phases: the direct transmission stage and the NOMA cooperative forwarding stage comprise the following steps:
(1) a direct transmission phase, which is carried out in the first half cycle of the cooperative communication period;
for ease of analysis, the present invention assumes that any one of the secondary users SU, ST, is selectedk-SRkAs a relay, the primary transmitter PT of the primary user PU broadcasts its data to the primary receiver PR and the transmitter ST of the secondary user SU selected as a relayk；
The primary receiver PR receives a signal yPT，PRAs shown in formula (I):
yPT，PR＝hPT，PRxP+ωPT，PR (Ⅰ)
in the formula (I), hPT，PRFor the channel gain, ω, between the primary transmitter PT and the primary receiver PRPT，PRIs white gaussian noise, x, between the primary transmitter PT and the primary receiver PRPIs a signal of a master user PU;
the direct transmission rate achieved by the primary receiver PR is:
SNRPT，PRindicating the signal-to-noise ratio of the signal sent from the primary transmitter PT to the primary receiver PR, resulting in a very small direct transmission rate R due to very poor channel conditions from the primary transmitter PT to the primary receiver PRdTherefore, SU must be selected as a relay for the PU's transmission. The invention considers the direct transmission rate R achieved by the primary receiver PRdNeglect;
transmitter ST of a secondary user SUkReceiving a signal
As shown in formula (II):
in the formula (II), the compound is shown in the specification,
for main transmitters PT and STkWhite gaussian noise in between, and the white gaussian noise,
for main transmitters PT and STkA channel gain in between;
(2) the NOMA cooperation forwarding stage is carried out in the second half period of the cooperation communication time interval;
for the secondary users SU, the invention assumes that each secondary user SU successfully decodes the signal received from the primary user PU in the first phase; therefore, the present invention is more focused onA relay process between the secondary user transmitter ST and the primary user receiver PR, secondary user receiver STk. Transmitter ST of a secondary user SUkA transmitter ST for a secondary user SU for decoding the signal received in the direct transmission phase and for superimposing it on the signal itself to generate a non-orthogonal signalkUsing NOMA transmission scheme, sharing frequency band and time resource, and forwarding power to optimal secondary user SU according to channel gain conditions of primary user PU and secondary user SU
Allocating different power allocation factors to primary user PU and secondary user SU
To distinguish signals of different users, i.e. to be
To a secondary user SU, will
Allocating to a master user PU; simultaneously forwarding non-orthogonal signals generated by superposition to receiver PR of primary user PU and receiver SR of secondary user SUkAnd at the receiver SR of the secondary user SUkAnd demodulating by a Serial Interference Cancellation (SIC) method at a receiver PR of the primary user PU, wherein the demodulation comprises the following steps: firstly, the information of the secondary user SU is taken as interference, the information of the primary user PU is decoded, and then the information of the secondary user SU is decoded; in the invention, a primary user PU and a secondary user SU share an authorized spectrum and formulate a power distribution factor to reward the forwarding of the SU in the demodulation process; thereby resolving the conflict of interests between the two.
The goal of the proposed cooperative NOMA system is to maximize the utility value of the selected SU while satisfying the basic transmission rate condition of the PU. The invention provides an optimization algorithm for jointly optimizing transmission power and power division factors. The objective function and the limiting conditions C1-C3 which satisfy the basic transmission rate condition of the primary user PU and simultaneously maximize the utility value of the selected secondary user SU are as shown in formula (III):
in the formula (III), USURefers to the utility value of the secondary user SU,
receiver SR at k-th secondary userkResulting transmission rate, α1kRefers to the power allocation factor, alpha, of the primary user PU2kRefers to the power allocation factor, λ, of the secondary user SUkRefers to the unit power consumption cost, P, of the secondary user SUkFor the forward power, P, of the secondary users SU in the transmissionMAXRefers to the power limit of the secondary user forwarding power; u shapePUMeans the utility value, R, of the primary user PUVThe method comprises the steps that a primary user PU obtains a required rate through NOMA cooperative transmission in an NOMA cooperative forwarding stage;
c1 shows that the utility value obtained by the main user PU in the multi-user relay communication system based on the cooperative NOMA is larger than the transmission rate R required by the main user PUV(ii) a C2 indicates that the power allocation factor is reasonable and that the power allocation factor of the primary user PU is always larger than that of the secondary user SU; c3 indicates that the forwarding power of the secondary user SU does not exceed PMAX；
Calculating the optimal SU forwarding power of the secondary user according to formula (III)
Optimal power allocation factor for primary user PU
And power allocation factor of secondary user SU
Respectively shown in formulas (IV), (V) and (VI):
in the formulas (IV), (V) and (VI), gamma refers to the transmission signal-to-interference-noise ratio required by the main user PU,
transmitter ST representing a secondary user SUkAnd the ratio of the channel gain and the noise power between the primary receivers PR of the primary users PU,
transmitter ST representing a secondary user SUkReceiver SR for secondary user SUkThe ratio of channel gain and noise power.
The invention solves the problem of selecting any SU as the best SU forwarding power when relaying
Optimal power allocation factor for primary user PU
And power allocation factor of secondary user SU
Can obtain each as a preparationAnd selecting the optimal resource allocation scheme of the system when the relay SU performs cooperative transmission.
The specific process is as follows:
1. assuming that the channel state is known, the primary user PU broadcasts a cooperative forwarding request to all secondary users SU that can act as alternative relays, indicating that it needs to seek a relay for cooperative NOMA transmission, and a power allocation factor scheme is given according to equations (v), (vi)
2. If the kth secondary user SU wants to perform cooperative transmission, the optimal secondary user SU forward power is calculated according to equation (IV)
And reporting the PU.
3. The PU of the master user receives the best SU forwarding power of the secondary users reported by all the k SU of the secondary users
The secondary user SU that maximizes the cooperative NOMA based multi-user relay communication system and rate is selected as the relay.
According to the invention, preferably, the inference process of the objective function in the NOMA cooperative forwarding stage is as follows:
successive Interference Cancellation (SIC) is applied to the primary receiver PR and the receiver SR for decoding non-orthogonal NOMA signals, and for the primary user PU, the information transmission rate obtained at the primary receiver PR is as shown in equation (vii):
in the formula (VII), the reaction mixture is,
σ2in order to be able to measure the power of the noise,
for the slave transmitter STkChannel gain, alpha, to the primary receiver PR1kIs the power allocation factor, alpha, of the primary user PU2kIs the power allocation factor of the secondary user SU; pkThe forward power of the secondary user SU in the transmission;
for the primary user PU, the present invention considers the direct transmission rate R due to the poor channel condition between PT and PRdNeglecting, setting the rate R required by the PU of the primary user through the NOMA cooperative transmission in the NOMA cooperative forwarding stageVDefinition of
γ is the required SINR (signal to interference plus noise ratio) of the primary user PU;
the utility function of the primary user PU is shown as formula (VIII):
it can be seen that the PU will seek to relay transmissions only when the direct transmission rate is small.
For secondary users SU, at the receiver SRkThe obtained information transmission rate is shown as formula (IX):
in the formula (IX),
σ2is the power of the noise or noise,
for the slave transmitter STkTo the receiver SRkThe channel gain of (a);
thus, the utility function of the secondary user SU is shown in formula (x):
in the formula (X), λkIs the unit power cost of the SU;
since the SU is selfish and rational, there is no obligation to waste power resources to help the PU forward information. In the proposed system, the invention maximizes the utility value of the secondary user SU in order to excite the SU, whereas for the primary user PU, it is only necessary to satisfy the PU's transmission rate to reach the requirement RVAnd R isVAlways greater than the direct transmission rate Rd；
The objective of the proposed cooperative NOMA system is to maximize the utility value of the selected secondary user SU while satisfying the basic transmission rate condition of the primary user PU. The objective function, constraint C1-C3 is shown as equation (III):
optimized SU forward power according to the invention
Optimal power allocation factor for primary user PU
And power allocation factor of secondary user SU
The reasoning process of the formulae (IV), (V), (VI) is as follows:
substituting restriction condition C2 into UPUAnd USUObtaining the formula (XI) or (XII):
the utility function of the secondary users SU is with respect to α2kIncrementally, obtained according to formula (XI)
Therefore, the secondary users SU are only present
Then there is a maximum utility value, at which time the yield of PU equals RV；
Although the yield of PU is equal to R at this timeVHowever, the PU still obtains a higher transmission rate than the direct transmission. The PU can still gain from cooperative transmission. The invention can simplify the optimization problem formula (III) and obtain the formula (XIII):
s.t.Pk≤PMAx
optimal SU forward power
The maximum utility of the secondary user SU is shown in formula (xiv):
solving the first and second reciprocal of formula (XIV), respectively as shown in formulas (XV) (XVI):
formula (xvi) is constantly negative, leading to the conclusion that: the maximum utility value is obtained when formula (XV) is zero, and thus the optimum SU forward power is calculated
Optimal power allocation factor for primary user PU
And power allocation factor of secondary user SU
As shown in formulas (IV), (V) and (VI):
preferably according to the invention, in order to maximize the throughput of the whole system, the secondary user SU is selected that maximizes the sum rateselectAs a relay, the purpose of improving the overall system performance can be achieved, as shown in formula (xvii):
in formula (xvii), K ═ 1, 2, K represents the K secondary relays that are candidates for relayingA set of users is provided with a user profile,
refers to the utility value obtained by the primary user PU when the kth secondary user is selected as the relay,
which means the utility value obtained by the secondary user SU when the kth secondary user is selected as the relay.
The invention has the beneficial effects that:
1. according to the power optimization relay selection method in the cooperative NOMA cooperative spectrum sharing system, the transmission rate of the cooperative NOMA system is analyzed, the properties of a logarithmic function are utilized, a corresponding utility function and an optimization problem are constructed, the optimized problem is researched, an optimal solution is obtained through a low-complexity solving algorithm, and the goal of maximizing the sum rate of the system is finally achieved.
2. The invention considers the fairness and the compatibility of resource allocation among users, fully considers the unique user requirements of a Secondary User (SU) and a Primary User (PU), and gives enough excitation to the SU to make the SU actively strive for the right of serving as a relay, so that the design of a communication system is more reasonable.
Drawings
FIG. 1 is a schematic representation of a cooperative NOMA based multi-user relay communication system model of the present invention;
FIG. 2 is a diagram illustrating simulation results of variation of ideal power allocation factors with SINR required by a primary user PU;
FIG. 3 is a diagram of simulation results of ideal SU relay power variation with the SINR required by a primary user PU;
FIG. 4 is a diagram illustrating a comparison of total utility values and a random strategy.
Detailed Description
The invention is further defined in the following, but not limited to, the figures and examples in the description.
Example 1
Secondary user strong incentive based on cooperative NOMA and cooperative spectrum sharingA power allocation method for operating in a cooperative NOMA based multi-user relay communication system, as shown in FIG. 1, the cooperative NOMA based multi-user relay communication system comprises a primary user system and a secondary user system, the primary user system is a primary user PU, the primary user PU comprises a primary transmitter PT and a primary receiver PR, the secondary user system comprises K secondary users SU, each secondary user SU comprises a transmitter and a receiver, forming a transmitter-receiver pair, denoted STk-SRkThe master user PU is always in a communication state;
the primary user PU has access to bandwidth, but the channel conditions for direct transmission between the PT and PR are poor. On the other hand, each SU wants to get spectrum access time to transmit its own signal. But the primary user PU controls the allocation of access bandwidth. Therefore, the SU must assist the PU in forwarding in order to have an opportunity to send its own signal. To make better use of bandwidth resources, a cooperative transmission strategy is used, comprising two transmission phases: the direct transmission stage and the NOMA cooperative forwarding stage comprise the following steps:
(1) a direct transmission phase, which is carried out in the first half cycle of the cooperative communication period;
for ease of analysis, the present invention assumes that any one of the secondary users SU, ST, is selectedk-SRkAs a relay, the primary transmitter PT of the primary user PU broadcasts its data to the primary receiver PR and the transmitter ST of the secondary user SU selected as a relayk；
The primary receiver PR receives a signal yPT，PRAs shown in formula (I):
yPT，PR＝hPT，PRxP+ωPT，PR (Ⅰ)
in the formula (I), hPT，PRFor the channel gain, ω, between the primary transmitter PT and the primary receiver PRPT，PRIs white gaussian noise, x, between the primary transmitter PT and the primary receiver PRPIs a signal of a master user PU;
the direct transmission rate achieved by the primary receiver PR is:
SNRPT，PRindicating the signal-to-noise ratio of the signal sent from the primary transmitter PT to the primary receiver PR, resulting in a very small direct transmission rate R due to very poor channel conditions from the primary transmitter PT to the primary receiver PRdTherefore, SU must be selected as a relay for the PU's transmission. The invention considers the direct transmission rate R achieved by the primary receiver PRdNeglect;
transmitter ST of a secondary user SUkReceiving a signal
As shown in formula (II):
in the formula (II), the compound is shown in the specification,
for main transmitters PT and STkWhite gaussian noise in between, and the white gaussian noise,
for main transmitters PT and STkA channel gain in between;
(2) the NOMA cooperation forwarding stage is carried out in the second half period of the cooperation communication time interval;
for the secondary users SU, the invention assumes that each secondary user SU successfully decodes the signal received from the primary user PU in the first phase; the invention therefore focuses more on the relay process between the secondary user sender ST and the primary user receiver PR, the secondary user receiver STk. Transmitter ST of a secondary user SUkDecoding the signal received in the direct transmission phase and superimposing it with the own signalTransmitter ST for secondary users SU, which are non-orthogonal signalskUsing NOMA transmission scheme, sharing frequency band and time resource, and forwarding power to optimal secondary user SU according to channel gain conditions of primary user PU and secondary user SU
Allocating different power allocation factors to secondary user SU and primary user PU
To distinguish signals of different users, i.e. to be
To a secondary user SU, will
Allocating to a master user PU; simultaneously forwarding non-orthogonal signals generated by superposition to receiver PR of primary user PU and receiver SR of secondary user SUkAnd at the receiver SR of the secondary user SUkAnd demodulating by a Serial Interference Cancellation (SIC) method at a receiver PR of the primary user PU, wherein the demodulation comprises the following steps: firstly, the information of the secondary user SU is taken as interference, the information of the primary user PU is decoded, and then the information of the secondary user SU is decoded; in the invention, a primary user PU and a secondary user SU share an authorized spectrum and formulate a power distribution factor to reward the forwarding of the SU in the demodulation process; thereby resolving the conflict of interests between the two.
The goal of the proposed cooperative NOMA system is to maximize the utility value of the selected SU while satisfying the basic transmission rate condition of the PU. The invention provides an optimization algorithm for jointly optimizing transmission power and power division factors. The objective function and the limiting conditions C1-C3 which satisfy the basic transmission rate condition of the primary user PU and simultaneously maximize the utility value of the selected secondary user SU are as shown in formula (III):
in the formula (III), USURefers to the utility value of the secondary user SU,
receiver SR at k-th secondary userkResulting transmission rate, α1kRefers to the power allocation factor, alpha, of the primary user PU2kRefers to the power allocation factor, λ, of the secondary user SUkRefers to the unit power consumption cost, P, of the secondary user SUkFor the forward power, P, of the secondary users SU in the transmissionMAXRefers to the power limit of the secondary user forwarding power; u shapePUMeans the utility value, R, of the primary user PUVThe method comprises the steps that a primary user PU obtains a required rate through NOMA cooperative transmission in an NOMA cooperative forwarding stage;
c1 shows that the utility value obtained by the main user PU in the multi-user relay communication system based on the cooperative NOMA is larger than the transmission rate R required by the main user PUV(ii) a C2 indicates that the power allocation factor is reasonable and that the power allocation factor of the primary user PU is always larger than that of the secondary user SU; c3 indicates that the forwarding power of the secondary user SU does not exceed PMAX；
Calculating the optimal SU forwarding power of the secondary user according to formula (III)
Optimal power allocation factor for primary user PU
And power allocation factor of secondary user SU
Respectively shown in formulas (IV), (V) and (VI):
in the formulas (IV), (V) and (VI), gamma refers to the transmission signal-to-interference-noise ratio required by the main user PU,
transmitter ST representing a secondary user SUkAnd the ratio of the channel gain and the noise power between the primary receivers PR of the primary users PU,
transmitter ST representing a secondary user SUkReceiver SR for secondary user SUkThe ratio of channel gain and noise power.
The invention solves the problem of selecting any SU as the best SU forwarding power when relaying
Optimal power allocation factor for primary user PU
And power allocation factor of secondary user SU
The optimal resource allocation scheme of the system when each SU as an alternative relay performs cooperative transmission can be obtained.
The specific process is as follows:
1. assuming the channel conditions are known, the primary user PU broadcasts to all available usersSending a cooperative forwarding request for the secondary users SU of the alternative relay indicating that they need to seek a relay for cooperative NOMA transmission, and providing a power allocation factor scheme according to equations (V), (VI)
2. If the kth secondary user SU wants to perform cooperative transmission, the optimal secondary user SU forward power is calculated according to equation (IV)
And reporting the PU.
3. The PU of the master user receives the best SU forwarding power of the secondary users reported by all the k SU of the secondary users
The secondary user SU that maximizes the cooperative NOMA based multi-user relay communication system and rate is selected as the relay.
In the NOMA cooperative forwarding phase, the reasoning process of the objective function is as follows:
successive Interference Cancellation (SIC) is applied to the primary receiver PR and the receiver SR for decoding non-orthogonal NOMA signals, and for the primary user PU, the information transmission rate obtained at the primary receiver PR is as shown in equation (vii):
in the formula (VII), the reaction mixture is,
σ2in order to be able to measure the power of the noise,
for the slave transmitter STkChannel gain, alpha, to the primary receiver PR1kIs the power allocation factor, alpha, of the primary user PU2kIs the power allocation factor of the secondary user SU; pkThe forward power of the secondary user SU in the transmission;
for the primary user PU, the present invention considers the direct transmission rate R due to the poor channel condition between PT and PRdNeglecting, setting the rate R required by the PU of the primary user through the NOMA cooperative transmission in the NOMA cooperative forwarding stageVDefinition of
γ is the required SINR (signal to interference plus noise ratio) of the primary user PU;
the utility function of the primary user PU is shown as formula (VIII):
it can be seen that the PU will seek to relay transmissions only when the direct transmission rate is small.
For secondary users SU, at the receiver SRkThe obtained information transmission rate is shown as formula (IX):
in the formula (IX),
σ2is the power of the noise or noise,
for the slave transmitter STkTo the receiver SRkThe channel gain of (a);
thus, the utility function of the secondary user SU is shown in formula (x):
in the formula (X), λkIs a unit of SUA power consumption cost;
since the SU is selfish and rational, there is no obligation to waste power resources to help the PU forward information. In the proposed system, the invention maximizes the utility value of the secondary user SU in order to excite the SU, whereas for the primary user PU, it is only necessary to satisfy the PU's transmission rate to reach the requirement RVAnd R isVAlways greater than the direct transmission rate Rd；
The objective of the proposed cooperative NOMA system is to maximize the utility value of the selected secondary user SU while satisfying the basic transmission rate condition of the primary user PU. The objective function, constraint C1-C3 is shown as equation (III):
optimal SU forward power
Optimal power allocation factor for primary user PU
And power allocation factor of secondary user SU
The reasoning process of the formulae (IV), (V), (VI) is as follows:
substituting restriction condition C2 into UPUAnd USEObtaining the formula (XI) or (XII):
for secondary useThe utility function of the user SU is with respect to alpha2kIncrementally, obtained according to formula (XI)
Therefore, the secondary users SU are only present
Then there is a maximum utility value, at which time the yield of PU equals RV；
Although the yield of PU is equal to R at this timeVHowever, the PU still obtains a higher transmission rate than the direct transmission. The PU can still gain from cooperative transmission. The invention can simplify the optimization problem formula (III) and obtain the formula (XIII):
s.t.Pk≤PMAX
optimal SU forward power
The maximum utility of the secondary user SU is shown in formula (xiv):
solving the first and second reciprocal of formula (XIV), respectively as shown in formulas (XV) (XVI):
formula (xvi) is constantly negative, leading to the conclusion that: when formula (XV) is zeroTo the maximum utility value, and thus, calculating the optimal SU forwarding power
Optimal power allocation factor for primary user PU
And power allocation factor of secondary user SU
As shown in formulas (IV), (V) and (VI):
the performance of a system based on cooperative NOMA and cooperative spectrum sharing proposed by the present embodiment is shown in fig. 2, 3 and 4. By comparison with random relay selection, take 5 SU relays as an example. FIG. 2 shows the ideal power division factor of the system
SINR as required by PU varies. It can be observed that a PU with a high required rate will achieve a greater power division factor
And assigns a smaller factor to SU
In FIG. 3, the invention illustrates the SIN of the desired PUContributing relay power of R and SU
The relationship between them. The higher the transmission required by the PU itself, the power consumed by SU forwarding
The less. Even if the PU allocates a greater power allocation factor when a greater rate is required, the SU will decrease the rate by decreasing the rate
To reduce its own losses, which also reflects the selfishness of the SU. This also represents a contradiction in the interests between the PU and SU, finding the most favorable points for both in the two mutual games. In fig. 4, the present invention compares the sum utility values of the proposed scheme and the random scheme. It can be seen that the total utility values of PU and SU are always higher than the random scheme. This demonstrates that the scheme of the present invention can be used to solve the optimal power allocation factor
And SU forward power
To achieve better performance of the overall system.
Example 2
The strong excitation power allocation method for the secondary users based on cooperative NOMA and cooperative spectrum sharing in embodiment 1 is characterized by comprising the following steps: to maximize the throughput of the overall system, the secondary user SU that maximizes the sum rate is selectedselectAs a relay, the purpose of improving the overall system performance can be achieved, as shown in formula (xvii):
in formula (xvii), K ═ {1, 2., K } represents the set of K secondary users that are candidates for relaying，
Refers to the utility value obtained by the primary user PU when the kth secondary user is selected as the relay,
which means the utility value obtained by the secondary user SU when the kth secondary user is selected as the relay.
Claims (4)
1. A secondary user strong excitation power distribution method based on cooperation NOMA and cooperation spectrum sharing is operated in a multi-user relay communication system based on cooperation NOMA, the multi-user relay communication system based on cooperation NOMA comprises a primary user system and a secondary user system, the primary user system refers to a primary user PU, the primary user PU comprises a primary transmitter PT and a primary receiver PR, the secondary user system comprises K secondary users SU, each secondary user SU comprises a transmitter and a receiver, and a transmitter-receiver pair is formed and is represented as STk-SRkThe master user PU is always in a communication state; it is characterized by comprising two transmission stages: the direct transmission stage and the NOMA cooperative forwarding stage comprise the following steps:
(1) a direct transmission phase, which is carried out in the first half cycle of the cooperative communication period;
selecting any one of the secondary users SU, STk-SRkAs a relay, the primary transmitter PT of the primary user PU broadcasts its data to the primary receiver PR and the transmitter ST of the secondary user SU selected as a relayk；
The primary receiver PR receives a signal yPT，PRAs shown in formula (I):
yPT，PR＝hPT，PRxP+ωPT，PR(I)
in the formula (I), hPT，PRFor the channel gain, ω, between the primary transmitter PT and the primary receiver PRPT，PRIs white gaussian noise, x, between the primary transmitter PT and the primary receiver PRPIs a signal of a master user PU;
direct transmission rate R achieved by the primary receiver PRdNeglect;
transmitter ST of a secondary user SUkReceiving a signal
As shown in formula (II):
in the formula (II), the compound is shown in the specification,
for main transmitters PT and STkWhite gaussian noise in between, and the white gaussian noise,
for main transmitters PT and STkA channel gain in between;
(2) the NOMA cooperation forwarding stage is carried out in the second half period of the cooperation communication time interval;
assuming that each secondary user SU successfully decodes the signal received from the primary user PU in the first phase; transmitter ST of a secondary user SUkA transmitter ST for a secondary user SU for decoding the signal received in the direct transmission phase and for superimposing it on the signal itself to generate a non-orthogonal signalkUsing NOMA transmission scheme, sharing frequency band and time resource, and forwarding power to optimal secondary user SU according to channel gain conditions of primary user PU and secondary user SU
Allocating different power allocation factors to the primary user PU and the secondary user SU
To distinguish the signals of the different users from each other,that is to say, the
To a secondary user SU, will
Allocating to a master user PU; simultaneously forwarding non-orthogonal signals generated by superposition to receiver PR of primary user PU and receiver SR of secondary user SUkAnd at the receiver SR of the secondary user SUkAnd demodulating by a serial interference elimination method at a receiver PR of the main user PU, wherein the demodulation comprises the following steps: firstly, the information of the secondary user SU is taken as interference, the information of the primary user PU is decoded, and then the information of the secondary user SU is decoded; in the demodulation process, a primary user PU rewards the forwarding of SU by sharing a licensed spectrum with a secondary user SU and formulating a power allocation factor;
the objective function and the limiting conditions C1-C3 that maximize the utility value of the selected secondary users SU while satisfying the basic transmission rate condition of the primary user PU are shown in equation (III):
in the formula (III), USURefers to the utility value of the secondary user SU,
receiver SR at k-th secondary userkResulting transmission rate, α1kRefers to the power allocation factor, alpha, of the primary user PU2kRefers to the power allocation factor, λ, of the secondary user SUkRefers to the unit power consumption cost, P, of the secondary user SUkFor the forward power, P, of the secondary users SU in the transmissionMAXRefers to the power limit of the secondary user forwarding power; u shapePUMeans the utility value, R, of the primary user PUVThe method comprises the steps that a primary user PU obtains a required rate through NOMA cooperative transmission in an NOMA cooperative forwarding stage;
c1 shows that the utility value obtained by the main user PU in the multi-user relay communication system based on the cooperative NOMA is larger than the transmission rate R required by the main user PUV(ii) a C2 indicates that the power allocation factor is reasonable and that the power allocation factor of the primary user PU is always larger than that of the secondary user SU; c3 indicates that the forwarding power of the secondary user SU does not exceed PMAX；
Calculating the optimal SU forwarding power of the secondary user by formula (III)
Optimal power allocation factor for primary user PU
And power allocation factor of secondary user SU
Respectively shown in formulas (IV), (V) and (VI):
in the formulas (IV), (V) and (VI), gamma refers to the transmission signal-to-interference-noise ratio required by the PU of the main user,
transmitter ST representing a secondary user SUkAnd the ratio of the channel gain and the noise power between the primary receivers PR of the primary users PU,
transmitter ST representing a secondary user SUkReceiver SR for secondary user SUkThe ratio of channel gain and noise power.
2. The method of claim 1, wherein the secondary users SU with the highest sum rate are selected to use strong excitation power allocation for secondary users sharing cooperative spectrum based on cooperative NOMAselectAs a relay, as shown in formula (xvii):
in the formula (XVII), the compound (VII),
representing a set of K secondary users that are alternatives to a relay,
refers to the utility value obtained by the primary user PU when the kth secondary user is selected as the relay,
which means the utility value obtained by the secondary user SU when the kth secondary user is selected as the relay.
3. The method for allocating strong excitation power to secondary users based on cooperative NOMA and cooperative spectrum sharing of claim 1, wherein in the NOMA cooperative forwarding stage, the information transmission rate obtained at the primary receiver PR is as shown in formula (vii):
in the formula (VII), the reaction mixture is,
σ2in order to be able to measure the power of the noise,
for the slave transmitter STkChannel gain, alpha, to the primary receiver PR1kIs the power allocation factor, alpha, of the primary user PU2kIs the power allocation factor of the secondary user SU; pkThe forward power of the secondary user SU in the transmission;
for the master user PU, direct transmission rate RdNeglecting, setting the rate R required by the PU of the primary user through the NOMA cooperative transmission in the NOMA cooperative forwarding stageVDefinition of
Gamma is the required SINR of the primary user PU;
the utility function of the primary user PU is shown as formula (VIII):
for secondary users SU, at the receiver SRkThe obtained information transmission rate is as shown in formula (IX):
in the formula (IX), the compound (I),
σ2is the power of the noise or noise,
for the slave transmitter STkTo the receiver SRkThe channel gain of (a);
the utility function of the secondary user SU is shown as equation (X):
in the formula (X), λkIs the unit power cost of the SU;
the utility value of the secondary user SU is maximized, and for the primary user PU, the transmission rate of the PU only needs to be met to reach the requirement RVAnd R isVAlways greater than the direct transmission rate Rd；
The utility value of the selected secondary user SU is maximized while the basic transmission rate condition of the primary user PU is met, and an objective function and a limiting condition C1-C3 are shown as formula (III):
4. method for strong excitation power allocation to secondary users based on cooperative NOMA and cooperative spectrum sharing according to any of claims 1-3, characterized in that the constraint C2 is substituted into UPUAnd USUTo obtain the formula (XI) and the formula (XII):
the utility function of the secondary users SU is with respect to α2kIncrementally, obtained according to formula (XI)
Therefore, the secondary users SU are only present
Then there is a maximum utility value, at which time the yield of PU equals RV；
Simplifying the optimization problem formula (III) to obtain formula (XIII):
optimal SU forward power
The maximum utility of the secondary user SU is shown in formula (xiv):
solving the first and second reciprocal of formula (XIV), respectively as shown in formulas (XV) (XVI):
formula (xvi) is constantly negative, leading to the conclusion that: the maximum utility value is obtained when formula (XV) is zero, and thus the optimum SU forward power is calculated
Optimal power allocation factor for primary user PU
And power allocation factor of secondary user SU
As shown in formulas (IV), (V) and (VI):
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104640220A (en) * | 2015-03-12 | 2015-05-20 | 重庆邮电大学 | A Frequency and Power Allocation Method Based on NOMA System |
| CN104661296A (en) * | 2013-11-25 | 2015-05-27 | 株式会社Ntt都科摩 | Device and method for deciding transmission power of user device |
| CN104702396A (en) * | 2015-04-07 | 2015-06-10 | 山东大学 | Joint resource allocation method for collaboration multi-relay cognitive system based on effectiveness |
| CN107105470A (en) * | 2017-03-29 | 2017-08-29 | 西安电子科技大学 | One kind takes can cooperate CR NOMA collaboration modes and relay selection algorithm |
| CN109982438A (en) * | 2019-04-08 | 2019-07-05 | 山东大学 | A kind of multi-user resource distributing method based under NOMA and SWIPT cognitive radio environment |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10757722B2 (en) * | 2016-03-25 | 2020-08-25 | Lg Electronics Inc. | Method for allowing wireless resource to be allocated in wireless communication system, and device therefor |
-
2019
- 2019-07-08 CN CN201910609094.5A patent/CN110324844B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104661296A (en) * | 2013-11-25 | 2015-05-27 | 株式会社Ntt都科摩 | Device and method for deciding transmission power of user device |
| CN104640220A (en) * | 2015-03-12 | 2015-05-20 | 重庆邮电大学 | A Frequency and Power Allocation Method Based on NOMA System |
| CN104702396A (en) * | 2015-04-07 | 2015-06-10 | 山东大学 | Joint resource allocation method for collaboration multi-relay cognitive system based on effectiveness |
| CN107105470A (en) * | 2017-03-29 | 2017-08-29 | 西安电子科技大学 | One kind takes can cooperate CR NOMA collaboration modes and relay selection algorithm |
| CN109982438A (en) * | 2019-04-08 | 2019-07-05 | 山东大学 | A kind of multi-user resource distributing method based under NOMA and SWIPT cognitive radio environment |
Non-Patent Citations (2)
| Title |
|---|
| Cooperative NOMA Based VLC/RF System with Simultaneous Wireless Information and Power Transfer;Zhou Xiaotian; Li Shanshan; Zhang Haixia;《: IEEE/CIC International Conference on Communications in China (ICCC)》;20180818;全文 * |
| Practical Power Allocation Schemes for Cooperative Relay Networking with NOMA;Jaeho Choi;Wei Duan;Haiyang Yu;Jinjuan Ju;《2018 IEEE/CIC International Conference on Comunicaitons in China(ICCC Workshops)》;20190328;全文 * |
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