CN104918257A - D2D communication resource allocation method in relay cooperative heterogeneous cellular network - Google Patents

Abstract

The invention discloses a D2D communication resource allocation method in a relay cooperative heterogeneous cellular network, comprising the following steps: solving the maximum achievable rate threshold R<Q(n),n><dmax>of D2D communication in a frequency band n when each cellular user n adopts a communication mode Q(n); judging whether spectrum resources selected for D2D communication can meet the requirement of the quality of service of a system according to R<Q(n),n><dmax>; jointly allocating the achievable rate target R<Q(n),n><d> allocated for D2D communication in the frequency band n when the cellular user n adopts the communication mode Q(n), and determining the communication mode Q(n) of each cellular user n; and solving the total transmitting power Ptotal of the system. By adopting the method, the transmitting power of cellular users and D2D users and the optimal achievable rate target of D2D users in each frequency band can be optimized at the same time, and the communication mode of each cellular user in the system can be determined. Compared with a traditional resource allocation method, the method can reduce the total power consumption of the system while ensuring the achievable rate of cellular users and D2D users, and is more in line with the requirement of green communication.

Description

Communication resource allocation method for relay cooperative heterogeneous cellular network D2D

Technical Field

The invention relates to a method in the technical field of wireless communication, in particular to a method for allocating Device-to-Device communication resources in a relay collaborative heterogeneous cellular network D2D.

Background

Wireless networks have evolved towards heterogeneous networks in order to meet the demand for spectrum resources and data rates for the dramatically increasing number of multimedia devices and services. With the rapid development of mobile communication, the rapid increase of multimedia devices and services causes the exponential increase of the load of the mobile traffic of a cell base station, which not only causes the mobile network to become congested, but also aggravates the energy consumption of the devices. In reality, spectrum resources are limited, energy consumption of equipment is limited, and how to effectively increase spectrum utilization rate and reduce energy consumption is a key research point.

The conventional cellular communication mode has been difficult to effectively solve the above-mentioned problems, so the concept of the D2D communication technology was introduced into the LTE network in 2009. The D2D communication can effectively relieve the mobile traffic load of the base station and reduce the energy consumption of the mobile network by establishing a direct transmission link which does not pass through the base station. By multiplexing the spectrum resources of cellular users by the D2D communication users, the system throughput, the spectrum efficiency and other performances can be effectively improved by utilizing the advantages of the D2D short-distance communication. However, the interference problem it introduces is the problem that wireless systems are the first to solve. Power control is a key technology for realizing spectrum resource sharing in a heterogeneous cellular network, and by reasonably controlling the power of cellular users and D2D users, when D2D communication accesses the authorized frequency band of the cellular users, the interference generated by D2D communication and cellular communication on each other can not affect the normal communication of the other.

In addition, the relay node is introduced at the edge of the cell, so that the problem of difficult communication between the cell edge user and the base station can be effectively solved, and the load of the base station can be relieved. With the development of relay technology and the wider application of relay technology to current networks, the power consumption of equipment can be significantly reduced, the coverage area of a cell can be improved, the transmission rate can be increased, and the like.

Most of the resource allocation methods adopted for D2D communication in the conventional heterogeneous cellular network are based on the goal of maximizing the total rate or the spectrum reuse rate of D2D communication on the premise of only guaranteeing the Quality of Service (QoS) of a single cellular user or the QoS of D2D communication, and at this time, the D2D communication needs to always maintain the maximum transmission power to transmit data. Obviously, this cannot guarantee QoS for both cellular and D2D users, nor meet the requirements for green communications.

Some conventional cellular networks only consider the case where a pair of D2D communications and one cellular user share spectrum resources. However, in practical environment, the number of cellular users is much higher than that of D2D users, and if a pair of D2D communication can only reuse the spectrum resource of one cellular user, it obviously causes a waste of spectrum resource.

Moreover, few cellular networks satisfy a multi-layer heterogeneous network model that includes both cellular users, D2D users, base stations, and relays.

Disclosure of Invention

The invention provides a resource allocation method based on optimal power allocation and cellular user communication mode (base station communication mode or relay coordination mode) selection, aiming at an uplink heterogeneous cellular network model with coexistence of a base station, a fixed relay, cellular users and D2D users. The invention allows a single D2D to multiplex spectrum resources of a plurality of cellular users, ensures the minimum reachable rate requirement on the single frequency band of the cellular users and the D2D users on the basis of the allocated spectrum resources, and simultaneously, optimizes the total power consumption of the whole system by jointly allocating the reachable rate target of the D2D users on each frequency band and the communication mode selection of the cellular users to meet the total reachable rate threshold requirement on all the multiplexed spectrum resources for the D2D users in order to fully utilize the advantage of D2D short-distance communication. The invention can simultaneously optimize the transmitting power of the cellular user and the D2D user, the optimal reachable rate target of the D2D user on each frequency band and determine the communication mode of each cellular user in the system. Compared with the traditional resource allocation method, the method can ensure the reachable rates of cellular users and D2D users, saves the total power consumption of the system and better meets the requirement of green communication.

The invention is realized by the following technical scheme.

The method for allocating the communication resources of the relay cooperative heterogeneous cellular network D2D provided by the invention comprises the following steps:

step 1: obtainingWhereinRepresents the maximum achievable rate threshold that D2D can achieve for communications over frequency band n when cellular user n adopts communication mode q (n);

step 2: according toJudging whether the frequency spectrum resources selected by D2D communication can meet the system service quality requirement;

and step 3: D2D communication on frequency band n when joint distribution cellular user n adopts communication mode Q (n)Assigned achievable rate targetAnd determining a communication mode q (n) of the cellular user n;

and 4, step 4: calculating the total transmission power P of the system^total。

Preferably, the step 3 specifically includes the following sub-steps:

step 3.1: initializing an initial communication pattern q (n) for each cellular user;

step 3.2: initializing lambda₁And λ₂And defining a weight function w_Q(n),n；

Step 3.3: determining cellular user n achievable rate targetA communication mode of (b), (n);

step 3.4: circularly solving reachable velocity threshold targetAnd a communication mode q (n) for cellular user n.

The above-mentionedIn order to obtain the maximum reachable rate threshold value of D2D communication on the frequency band n when the cellular user n adopts the Q (n) communication mode, the minimum reachable rate threshold value requirements of cellular communication and D2D communication on a single frequency band are obtainedThe expression is as follows:

<math> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <msubsup> <mi>R</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mrow> <mi>d</mi> <mi>max</mi> </mrow> </msubsup> <mo>=</mo> <msub> <mi>log</mi> <mn>2</mn> </msub> <mrow> <mo>(</mo> <mn>1</mn> <mo>+</mo> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mrow> <mi>d</mi> <mi>max</mi> </mrow> </msubsup> <mo>)</mo> </mrow> </mtd> </mtr> <mtr> <mtd> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mrow> <mi>d</mi> <mi>max</mi> </mrow> </msubsup> <mo>=</mo> <mfrac> <mrow> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>c</mi> </msubsup> <msup> <mi>g</mi> <mi>d</mi> </msup> </mrow> <mrow> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>dc</mi> </msubsup> <msubsup> <mi>g</mi> <mi>n</mi> <mi>cd</mi> </msubsup> </mrow> </mfrac> <msup> <mrow> <mo>(</mo> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mrow> <mi>c</mi> <mi>min</mi> </mrow> </msubsup> <mo>)</mo> </mrow> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> </mtd> </mtr> </mtable> </mfenced> </math>

wherein, cellular user n is the nth cellular user, and frequency band n is the nth frequency band; n is 1,2, …, N represents the total number of cellular users;is composed ofThe corresponding SINR (signal to interference plus noise ratio), g^d，respectively showing the cellular link channel gain of the cellular user n in the communication mode Q (n), the D2D link channel gain, the link channel gain from the cellular user n to the D2D communication receiving terminal and the link channel gain from the D2D transmitting terminal to the cellular user n receiving terminal; q (n) {1,2}, q (n) ═ 1, q (n) ═ 2 denote that cellular user n employs the base station communication mode and the relay coordination mode, respectively, and it is assumed that cellular user n uses frequency band n;minimum reachable rate threshold for D2D communication on frequency band n when cellular user n adopts communication mode Q (n)Corresponding SINR, and the minimum achievable rate threshold of D2D communication on the frequency band n when the cellular user n adopts the relay coordination modeIs the minimum reachable rate threshold of D2D communication on the frequency band n when the cellular user n adopts the base station communication modeTwice as much as the amount of the first,

preferably, said in step 2 is according toThe judgment criterion expression for judging whether the spectrum resources selected by the D2D communication can meet the system service quality requirement is as follows:

<math> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <munder> <mi>max</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> </mrow> </munder> <mrow> <mo>(</mo> <msubsup> <mi>R</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mrow> <mi>d</mi> <mi>max</mi> </mrow> </msubsup> <mo>)</mo> </mrow> <mo>></mo> <msubsup> <mi>R</mi> <mi>n</mi> <mrow> <mi>d</mi> <mi>min</mi> </mrow> </msubsup> <mo>,</mo> <mo>&ForAll;</mo> <mi>n</mi> <mo>.</mo> </mtd> </mtr> <mtr> <mtd> <msubsup> <mi>R</mi> <mi>all</mi> <mrow> <mi>d</mi> <mi>max</mi> </mrow> </msubsup> <mo>=</mo> <munderover> <mi>&Sigma;</mi> <mrow> <mi>n</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>N</mi> </munderover> <munder> <mi>max</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> </mrow> </munder> <mrow> <mo>(</mo> <msubsup> <mi>R</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mrow> <mi>d</mi> <mi>max</mi> </mrow> </msubsup> <mo>)</mo> </mrow> <mo>></mo> <msubsup> <mi>R</mi> <mi>all</mi> <mi>d</mi> </msubsup> </mtd> </mtr> </mtable> </mfenced> </math>

if the above formula is satisfied, the service quality requirement is satisfied; wherein,representing the minimum achievable rate threshold for D2D communication over frequency band n,representing the maximum achievable total achievable rate of D2D communication over all multiplexed N frequency bands,represents the total achievable rate threshold of the D2D communication over all the multiplexed N frequency bands;indicating that the maximum value in brackets is selected under different cellular communication modes q (n).

Preferably, the initial communication mode q (n) of each cellular user is initialized in step 3.1 to satisfy the following criteria:

<math> <mrow> <msubsup> <mi>R</mi> <mi>all</mi> <mrow> <mi>d</mi> <mi>max</mi> </mrow> </msubsup> <mo>=</mo> <munderover> <mi>&Sigma;</mi> <mrow> <mi>n</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>N</mi> </munderover> <munder> <mi>max</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> </mrow> </munder> <mrow> <mo>(</mo> <msubsup> <mi>R</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mrow> <mi>d</mi> <mi>max</mi> </mrow> </msubsup> <mo>)</mo> </mrow> <mo>></mo> <msubsup> <mi>R</mi> <mi>all</mi> <mi>d</mi> </msubsup> <mo>.</mo> </mrow> </math>

in said step 3.2 λ is initialized₁And λ₂The following criteria are satisfied:wherein λ is₁、λ₂Respectively selecting a smaller Lagrange multiplier and a larger Lagrange multiplier;r (λ) represents the total achievable rate allocated by D2D communication over all N frequency bands at the value of λ;in order to define the weight function,the achievable rate targets assigned for D2D communication in frequency band n, based on the cellular user n assuming cellular communication mode q (n), are variables for the lagrangian multiplier lambda,the expression of (a) is:

<math> <mrow> <msubsup> <mi>R</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>d</mi> </msubsup> <mo>=</mo> <msub> <mi>log</mi> <mn>2</mn> </msub> <mrow> <mo>(</mo> <mn>1</mn> <mo>+</mo> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>d</mi> </msubsup> <mrow> <mo>(</mo> <mi>&lambda;</mi> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mo>;</mo> </mrow> </math>

wherein,

<math> <mfenced open='' close=''> <mtable> <mtr> <mtd> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>d</mi> </msubsup> <mrow> <mo>(</mo> <mi>&lambda;</mi> <mo>)</mo> </mrow> <mo>=</mo> <mfrac> <mrow> <msub> <mrow> <mo>-</mo> <mi>Y</mi> </mrow> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>&lambda;</mi> <mo>)</mo> </mrow> <mo>-</mo> <msqrt> <msub> <mi>Y</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> </msub> <msup> <mrow> <mo>(</mo> <mi>&lambda;</mi> <mo>)</mo> </mrow> <mn>2</mn> </msup> <mo>-</mo> <msub> <mrow> <mn>4</mn> <mi>X</mi> </mrow> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>&lambda;</mi> <mo>)</mo> </mrow> <msub> <mi>Z</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>&lambda;</mi> <mo>)</mo> </mrow> </msqrt> </mrow> <mrow> <msub> <mrow> <mn>2</mn> <mi>X</mi> </mrow> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>&lambda;</mi> <mo>)</mo> </mrow> </mrow> </mfrac> </mtd> </mtr> <mtr> <mtd> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <msub> <mi>X</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>&lambda;</mi> <mo>)</mo> </mrow> <mo>=</mo> <msup> <mrow> <mo>(</mo> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>dc</mi> </msubsup> <mo>&CenterDot;</mo> <msubsup> <mi>g</mi> <mi>n</mi> <mi>cd</mi> </msubsup> <mo>)</mo> </mrow> <mn>2</mn> </msup> <mo>&CenterDot;</mo> <mi>&lambda;</mi> <mo>,</mo> </mtd> </mtr> <mtr> <mtd> <msub> <mi>Y</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>&lambda;</mi> <mo>)</mo> </mrow> <mo>=</mo> <mo>-</mo> <mn>2</mn> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>c</mi> </msubsup> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>dc</mi> </msubsup> <mo>&CenterDot;</mo> <msubsup> <mi>g</mi> <mi>n</mi> <mi>cd</mi> </msubsup> <msup> <mi>g</mi> <mi>d</mi> </msup> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <msup> <mrow> <mi>c</mi> <mi>min</mi> </mrow> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> </msubsup> <mi>&lambda;</mi> <mo>-</mo> <msub> <mi>F</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>Z</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>&lambda;</mi> <mo>)</mo> </mrow> <mo>=</mo> <msup> <mrow> <mo>(</mo> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>c</mi> </msubsup> <msup> <mi>g</mi> <mi>d</mi> </msup> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <msup> <mrow> <mi>c</mi> <mi>min</mi> </mrow> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> </msubsup> <mo>)</mo> </mrow> <mn>2</mn> </msup> <mi>&lambda;</mi> <mo>-</mo> <msub> <mi>F</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>F</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> </msub> <mo>=</mo> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>c</mi> </msubsup> <mrow> <mo>(</mo> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>c</mi> </msubsup> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <msup> <mrow> <mi>c</mi> <mi>min</mi> </mrow> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> </msubsup> <mo>+</mo> <msubsup> <mi>g</mi> <mi>n</mi> <mi>cd</mi> </msubsup> <mo>)</mo> </mrow> <msup> <mi>g</mi> <mi>d</mi> </msup> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <msup> <mrow> <mi>c</mi> <mi>min</mi> </mrow> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> </msubsup> <msub> <mi>N</mi> <mn>0</mn> </msub> </mtd> </mtr> </mtable> </mfenced> </mtd> </mtr> </mtable> </mfenced> </math>

represents the minimum SINR threshold value of the cellular user N on the frequency band N by adopting the communication mode Q (N), the superscript-1 represents the power of-1, N₀Representing system noise;in the cellular communication mode q (n) adopted for the cellular user n, the SINR target on the frequency band n allocated to D2D communication is a variable related to the lagrangian multiplier λ, and needs to satisfy:wherein,minimum achievable rate threshold over frequency band n for D2D communicationA corresponding SINR value;are respectively corresponding toAnd Q (n), the optimal transmit power for cellular users n, D2D users on band n,the expression of (a) is:

<math> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <msubsup> <mi>P</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>c</mi> </msubsup> <mo>=</mo> <mfrac> <mrow> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>dc</mi> </msubsup> <mo>+</mo> <msup> <mi>g</mi> <mi>d</mi> </msup> <msup> <mrow> <mo>(</mo> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>d</mi> </msubsup> <mrow> <mo>(</mo> <mi>&lambda;</mi> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> </mrow> <mrow> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>c</mi> </msubsup> <msup> <mrow> <mo>(</mo> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mrow> <mi>c</mi> <mi>min</mi> </mrow> </msubsup> <mo>)</mo> </mrow> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> <msup> <mi>g</mi> <mi>d</mi> </msup> <msup> <mrow> <mo>(</mo> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>d</mi> </msubsup> <mrow> <mo>(</mo> <mi>&lambda;</mi> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> <mo>-</mo> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>dc</mi> </msubsup> <msubsup> <mi>g</mi> <mi>n</mi> <mi>cd</mi> </msubsup> </mrow> </mfrac> <mo>.</mo> <msub> <mi>N</mi> <mn>0</mn> </msub> </mtd> </mtr> <mtr> <mtd> <msubsup> <mi>P</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>d</mi> </msubsup> <mo>=</mo> <mfrac> <mrow> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>c</mi> </msubsup> <msup> <mrow> <mo>(</mo> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mrow> <mi>c</mi> <mi>min</mi> </mrow> </msubsup> <mo>)</mo> </mrow> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> <mo>+</mo> <msubsup> <mi>g</mi> <mi>n</mi> <mi>cd</mi> </msubsup> </mrow> <mrow> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>c</mi> </msubsup> <msup> <mrow> <mo>(</mo> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mrow> <mi>c</mi> <mi>min</mi> </mrow> </msubsup> <mo>)</mo> </mrow> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> <msup> <mi>g</mi> <mi>d</mi> </msup> <msup> <mrow> <mo>(</mo> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>d</mi> </msubsup> <mrow> <mo>(</mo> <mi>&lambda;</mi> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> <mo>-</mo> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>dc</mi> </msubsup> <msubsup> <mi>g</mi> <mi>n</mi> <mi>cd</mi> </msubsup> </mrow> </mfrac> <mo>.</mo> <msub> <mi>N</mi> <mn>0</mn> </msub> </mtd> </mtr> </mtable> </mfenced> </math>

said step 3.3 cellular user n is at reachable rate thresholdThe determination criterion of the communication mode q (n) below is:

$Q\left(n\right)=\arg \underset{Q\left(n\right)}{\min }{w}_{Q\left(n\right),n}$

i.e. cellular subscriber n is in correspondenceIs selected at a value of w_Q(n),nThe lowest value of the communication modes Q (n), in which <math> <mrow> <mi>&lambda;</mi> <mo>=</mo> <mfrac> <mrow> <msub> <mi>&lambda;</mi> <mn>1</mn> </msub> <mo>+</mo> <msub> <mi>&lambda;</mi> <mn>2</mn> </msub> </mrow> <mn>2</mn> </mfrac> <mo>;</mo> </mrow> </math>

The achievable rate threshold target in step 3.4And the cyclic solution criterion of the communication mode Q (n) of the cellular user n is as follows:

if it isReturning the corresponding Q (n),λ^*and go to step 4; otherwise, ifLet lambda₂λ and return to step 3.3; if it isLet lambda₁λ and return to step 3.3;

r (λ) represents the total achievable rate allocated by D2D communication over all N frequency bands at the value of λ; representing the precision of the dichotomy;the optimal reachable rate threshold assigned to D2D communication in frequency band n when cellular user n adopts communication mode q (n) is determined by lagrangian multiplier λ^*A variable of (d); lambda [ alpha ]^*Representing the optimal lagrangian multiplier obtained when the loop is stopped.

The P is^totalThe expression is the total transmission power of the system:

<math> <mrow> <msup> <mi>P</mi> <mi>total</mi> </msup> <mo>=</mo> <munderover> <mi>&Sigma;</mi> <mrow> <mi>n</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>N</mi> </munderover> <mrow> <mo>(</mo> <msubsup> <mi>P</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>c</mi> </msubsup> <mrow> <mo>(</mo> <msup> <mi>&lambda;</mi> <mo>*</mo> </msup> <mo>)</mo> </mrow> <mo>+</mo> <msubsup> <mi>P</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>d</mi> </msubsup> <mrow> <mo>(</mo> <msup> <mi>&lambda;</mi> <mo>*</mo> </msup> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mo>.</mo> </mrow> </math>

wherein,andrespectively representing the optimal Lagrange multiplier lambda^*And q (n), the optimal transmit power for cellular users n, D2D users on frequency band n.

Compared with the prior art, the invention has the following beneficial effects:

the invention can simultaneously optimize the transmitting power of the cellular user and the D2D user, the optimal reachable rate target of the D2D user on each frequency band and determine the communication mode of each cellular user in the system. Compared with the traditional resource allocation method, the method can ensure the reachable rates of cellular users and D2D users, saves the total power consumption of the system and better meets the requirement of green communication.

Drawings

FIG. 1 is a flow chart of the present invention;

FIG. 2 is a graph illustrating the total achievable rate requirement for D2D communication according to the present inventionA graph of overall system power consumption and D2D communication power consumption as it increased from 30bps/Hz to 46 bps/Hz;

FIG. 3 is a graph of the system and D2D communication power consumption for the present invention when the D2D communication distance is increased from 10 meters to 30 meters;

fig. 4 is a graph of the average total power consumption of the system of the present invention over a single frequency band from group 1 to group 10 based on the group of cellular users whose distances to the base stations are gradually increased.

Detailed Description

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings: the present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments.

The embodiment is a D2D resource allocation scheme based on relay coordination and power control, the system noise is zero-mean additive white gaussian noise with a spectral density of-174 dBm/Hz, the distance from the relay to the base station is 400 meters, and the channel model considers a simple path loss model: g ═ d^-α. Where g denotes channel gain, d denotes distance, and α denotes path fading index, where α is taken to be 3.

The embodiment comprises the following steps:

step 1: obtainingWhereinWhen the cellular user n adopts the communication mode q (n), the maximum reachable rate threshold value that can be reached by D2D communication on the frequency band n is obtained according to the minimum reachable rate threshold requirement of cellular communication and D2D communication on a single frequency band, and the expression is as follows:

<math> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <msubsup> <mi>R</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mrow> <mi>d</mi> <mi>max</mi> </mrow> </msubsup> <mo>=</mo> <msub> <mi>log</mi> <mn>2</mn> </msub> <mrow> <mo>(</mo> <mn>1</mn> <mo>+</mo> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mrow> <mi>d</mi> <mi>max</mi> </mrow> </msubsup> <mo>)</mo> </mrow> </mtd> </mtr> <mtr> <mtd> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mrow> <mi>d</mi> <mi>max</mi> </mrow> </msubsup> <mo>=</mo> <mfrac> <mrow> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>c</mi> </msubsup> <msup> <mi>g</mi> <mi>d</mi> </msup> </mrow> <mrow> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>dc</mi> </msubsup> <msubsup> <mi>g</mi> <mi>n</mi> <mi>cd</mi> </msubsup> </mrow> </mfrac> <msup> <mrow> <mo>(</mo> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mrow> <mi>c</mi> <mi>min</mi> </mrow> </msubsup> <mo>)</mo> </mrow> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> </mtd> </mtr> </mtable> </mfenced> </math>

wherein, cellular user n is the nth cellular user, and frequency band n is the nth frequency band; n is 1,2, …, N represents the total number of cellular users;is composed ofThe corresponding SINR (signal to interference plus noise ratio), g^d,respectively showing the cellular link channel gain of the cellular user n in the communication mode Q (n), the D2D link channel gain, the link channel gain from the cellular user n to the D2D communication receiving terminal and the link channel gain from the D2D transmitting terminal to the cellular user n receiving terminal; q (n) {1,2}, q (n) ═ 1, q (n) ═ 2 denote that cellular user n employs the base station communication mode and the relay coordination mode, respectively, and it is assumed that cellular user n uses frequency band n;minimum reachable rate threshold for D2D communication on frequency band n when cellular user n adopts communication mode Q (n)Corresponding SINR, and the minimum achievable rate threshold of D2D communication on the frequency band n when the cellular user n adopts the relay coordination modeIs the minimum reachable rate threshold of D2D communication on the frequency band n when the cellular user n adopts the base station communication modeTwice as much as the amount of the first,

step 2: according toJudging whether the frequency spectrum resource selected by the D2D communication can meet the system service quality requirement, wherein the judgment criteria are as follows:

<math> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <munder> <mi>max</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> </mrow> </munder> <mrow> <mo>(</mo> <msubsup> <mi>R</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mrow> <mi>d</mi> <mi>max</mi> </mrow> </msubsup> <mo>)</mo> </mrow> <mo>></mo> <msubsup> <mi>R</mi> <mi>n</mi> <mrow> <mi>d</mi> <mi>min</mi> </mrow> </msubsup> <mo>,</mo> <mo>&ForAll;</mo> <mi>n</mi> <mo>.</mo> </mtd> </mtr> <mtr> <mtd> <msubsup> <mi>R</mi> <mi>all</mi> <mrow> <mi>d</mi> <mi>max</mi> </mrow> </msubsup> <mo>=</mo> <munderover> <mi>&Sigma;</mi> <mrow> <mi>n</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>N</mi> </munderover> <munder> <mi>max</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> </mrow> </munder> <mrow> <mo>(</mo> <msubsup> <mi>R</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mrow> <mi>d</mi> <mi>max</mi> </mrow> </msubsup> <mo>)</mo> </mrow> <mo>></mo> <msubsup> <mi>R</mi> <mi>all</mi> <mi>d</mi> </msubsup> </mtd> </mtr> </mtable> </mfenced> </math>

if the above formula is satisfied, the service quality requirement is satisfied; wherein,representing the minimum achievable rate threshold for D2D communication over frequency band n,representing the maximum achievable total achievable rate of D2D communication over all multiplexed N frequency bands,represents the total achievable rate threshold of the D2D communication over all the multiplexed N frequency bands;means for selecting the maximum value in brackets under different cellular communication modes Q (n)_。

And step 3: allocation of reachable rate targets allocated on frequency band n by D2D communication when cellular user n adopts communication mode Q (n)And determining a communication mode q (n) of the cellular user n, comprising the sub-steps of:

step 3.1: an initial communication mode q (n) for each cellular user is initialized, the criteria that need to be met are as follows:

<math> <mrow> <msubsup> <mi>R</mi> <mi>all</mi> <mrow> <mi>d</mi> <mi>max</mi> </mrow> </msubsup> <mo>=</mo> <munderover> <mi>&Sigma;</mi> <mrow> <mi>n</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>N</mi> </munderover> <munder> <mi>max</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> </mrow> </munder> <mrow> <mo>(</mo> <msubsup> <mi>R</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mrow> <mi>d</mi> <mi>max</mi> </mrow> </msubsup> <mo>)</mo> </mrow> <mo>></mo> <msubsup> <mi>R</mi> <mi>all</mi> <mi>d</mi> </msubsup> <mo>.</mo> </mrow> </math>

step 3.2: initializing lambda₁And λ₂And defining a weight function w_Q(n),n，λ₁And λ₂The initialization criteria of (a) are as follows:wherein λ is₁、λ₂Respectively selecting a smaller Lagrange multiplier and a larger Lagrange multiplier;r (λ) represents the total achievable rate allocated by D2D communication over all N frequency bands at the value of λ;in order to define the weight function,cellular communication mode Q (n) allocation for D2D communication on frequency band n based on cellular user nThe achievable rate target, is a variable on the lagrangian multiplier lambda,the expression of (a) is:

<math> <mrow> <msubsup> <mi>R</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>d</mi> </msubsup> <mo>=</mo> <msub> <mi>log</mi> <mn>2</mn> </msub> <mrow> <mo>(</mo> <mn>1</mn> <mo>+</mo> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>d</mi> </msubsup> <mrow> <mo>(</mo> <mi>&lambda;</mi> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mo>;</mo> </mrow> </math>

wherein,

<math> <mfenced open='' close=''> <mtable> <mtr> <mtd> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>d</mi> </msubsup> <mrow> <mo>(</mo> <mi>&lambda;</mi> <mo>)</mo> </mrow> <mo>=</mo> <mfrac> <mrow> <msub> <mrow> <mo>-</mo> <mi>Y</mi> </mrow> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>&lambda;</mi> <mo>)</mo> </mrow> <mo>-</mo> <msqrt> <msub> <mi>Y</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> </msub> <msup> <mrow> <mo>(</mo> <mi>&lambda;</mi> <mo>)</mo> </mrow> <mn>2</mn> </msup> <mo>-</mo> <msub> <mrow> <mn>4</mn> <mi>X</mi> </mrow> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>&lambda;</mi> <mo>)</mo> </mrow> <msub> <mi>Z</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>&lambda;</mi> <mo>)</mo> </mrow> </msqrt> </mrow> <mrow> <msub> <mrow> <mn>2</mn> <mi>X</mi> </mrow> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>&lambda;</mi> <mo>)</mo> </mrow> </mrow> </mfrac> </mtd> </mtr> <mtr> <mtd> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <msub> <mi>X</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>&lambda;</mi> <mo>)</mo> </mrow> <mo>=</mo> <msup> <mrow> <mo>(</mo> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>dc</mi> </msubsup> <mo>&CenterDot;</mo> <msubsup> <mi>g</mi> <mi>n</mi> <mi>cd</mi> </msubsup> <mo>)</mo> </mrow> <mn>2</mn> </msup> <mo>&CenterDot;</mo> <mi>&lambda;</mi> <mo>,</mo> </mtd> </mtr> <mtr> <mtd> <msub> <mi>Y</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>&lambda;</mi> <mo>)</mo> </mrow> <mo>=</mo> <mo>-</mo> <mn>2</mn> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>c</mi> </msubsup> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>dc</mi> </msubsup> <mo>&CenterDot;</mo> <msubsup> <mi>g</mi> <mi>n</mi> <mi>cd</mi> </msubsup> <msup> <mi>g</mi> <mi>d</mi> </msup> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <msup> <mrow> <mi>c</mi> <mi>min</mi> </mrow> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> </msubsup> <mi>&lambda;</mi> <mo>-</mo> <msub> <mi>F</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>Z</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>&lambda;</mi> <mo>)</mo> </mrow> <mo>=</mo> <msup> <mrow> <mo>(</mo> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>c</mi> </msubsup> <msup> <mi>g</mi> <mi>d</mi> </msup> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <msup> <mrow> <mi>c</mi> <mi>min</mi> </mrow> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> </msubsup> <mo>)</mo> </mrow> <mn>2</mn> </msup> <mi>&lambda;</mi> <mo>-</mo> <msub> <mi>F</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>F</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> </msub> <mo>=</mo> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>c</mi> </msubsup> <mrow> <mo>(</mo> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>c</mi> </msubsup> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <msup> <mrow> <mi>c</mi> <mi>min</mi> </mrow> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> </msubsup> <mo>+</mo> <msubsup> <mi>g</mi> <mi>n</mi> <mi>cd</mi> </msubsup> <mo>)</mo> </mrow> <msup> <mi>g</mi> <mi>d</mi> </msup> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <msup> <mrow> <mi>c</mi> <mi>min</mi> </mrow> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> </msubsup> <msub> <mi>N</mi> <mn>0</mn> </msub> </mtd> </mtr> </mtable> </mfenced> </mtd> </mtr> </mtable> </mfenced> </math>

represents the minimum SINR threshold value of the cellular user N on the frequency band N by adopting the communication mode Q (N), the superscript-1 represents the power of-1, N₀Representing system noise;in the cellular communication mode q (n) adopted for the cellular user n, the SINR target on the frequency band n allocated to D2D communication is a variable related to the lagrangian multiplier λ, and needs to satisfy:wherein,minimum achievable rate threshold over frequency band n for D2D communicationA corresponding SINR value;are respectively corresponding toAnd Q (n), the optimal transmit power for cellular users n, D2D users on band n,the expression of (a) is:

<math> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <msubsup> <mi>P</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>c</mi> </msubsup> <mo>=</mo> <mfrac> <mrow> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>dc</mi> </msubsup> <mo>+</mo> <msup> <mi>g</mi> <mi>d</mi> </msup> <msup> <mrow> <mo>(</mo> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>d</mi> </msubsup> <mrow> <mo>(</mo> <mi>&lambda;</mi> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> </mrow> <mrow> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>c</mi> </msubsup> <msup> <mrow> <mo>(</mo> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mrow> <mi>c</mi> <mi>min</mi> </mrow> </msubsup> <mo>)</mo> </mrow> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> <msup> <mi>g</mi> <mi>d</mi> </msup> <msup> <mrow> <mo>(</mo> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>d</mi> </msubsup> <mrow> <mo>(</mo> <mi>&lambda;</mi> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> <mo>-</mo> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>dc</mi> </msubsup> <msubsup> <mi>g</mi> <mi>n</mi> <mi>cd</mi> </msubsup> </mrow> </mfrac> <mo>.</mo> <msub> <mi>N</mi> <mn>0</mn> </msub> </mtd> </mtr> <mtr> <mtd> <msubsup> <mi>P</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>d</mi> </msubsup> <mo>=</mo> <mfrac> <mrow> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>c</mi> </msubsup> <msup> <mrow> <mo>(</mo> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mrow> <mi>c</mi> <mi>min</mi> </mrow> </msubsup> <mo>)</mo> </mrow> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> <mo>+</mo> <msubsup> <mi>g</mi> <mi>n</mi> <mi>cd</mi> </msubsup> </mrow> <mrow> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>c</mi> </msubsup> <msup> <mrow> <mo>(</mo> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mrow> <mi>c</mi> <mi>min</mi> </mrow> </msubsup> <mo>)</mo> </mrow> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> <msup> <mi>g</mi> <mi>d</mi> </msup> <msup> <mrow> <mo>(</mo> <msubsup> <mi>&gamma;</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>d</mi> </msubsup> <mrow> <mo>(</mo> <mi>&lambda;</mi> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> <mo>-</mo> <msubsup> <mi>g</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>dc</mi> </msubsup> <msubsup> <mi>g</mi> <mi>n</mi> <mi>cd</mi> </msubsup> </mrow> </mfrac> <mo>.</mo> <msub> <mi>N</mi> <mn>0</mn> </msub> </mtd> </mtr> </mtable> </mfenced> </math>

step 3.3: determining cellular user n at reachable rate thresholdA communication mode q (n) of the following, which determines the criterion:

$Q\left(n\right)=\arg \underset{Q\left(n\right)}{\min }{w}_{Q\left(n\right),n}$

i.e. cellular subscriber n is in correspondenceIs selected at a value of w_Q(n),nThe lowest value of the communication modes Q (n), in which <math> <mrow> <mi>&lambda;</mi> <mo>=</mo> <mfrac> <mrow> <msub> <mi>&lambda;</mi> <mn>1</mn> </msub> <mo>+</mo> <msub> <mi>&lambda;</mi> <mn>2</mn> </msub> </mrow> <mn>2</mn> </mfrac> <mo>.</mo> </mrow> </math>

Step 3.4: circularly solving reachable velocity threshold targetAnd a communication mode Q (n) of the cellular user n, wherein the cycle criterion is as follows:

if it isReturning the corresponding Q (n),λ^*and go to step 4; otherwise, ifLet lambda₂λ and return to step 3.3; if it isLet lambda₁λ and return to step 3.3;

r (λ) represents the total achievable rate allocated by D2D communication over all N frequency bands at the value of λ; representing the precision of the dichotomy;the optimal reachable rate threshold assigned to D2D communication in frequency band n when cellular user n adopts communication mode q (n) is determined by lagrangian multiplier λ^*A variable of (d); lambda [ alpha ]^*Representing the optimal lagrangian multiplier obtained when the loop is stopped.

And 4, step 4: calculating the total transmission power P of the system^total，P^totalThe expression of (a) is as follows:

<math> <mrow> <msup> <mi>P</mi> <mi>total</mi> </msup> <mo>=</mo> <munderover> <mi>&Sigma;</mi> <mrow> <mi>n</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>N</mi> </munderover> <mrow> <mo>(</mo> <msubsup> <mi>P</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>c</mi> </msubsup> <mrow> <mo>(</mo> <msup> <mi>&lambda;</mi> <mo>*</mo> </msup> <mo>)</mo> </mrow> <mo>+</mo> <msubsup> <mi>P</mi> <mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>n</mi> </mrow> <mi>d</mi> </msubsup> <mrow> <mo>(</mo> <msup> <mi>&lambda;</mi> <mo>*</mo> </msup> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mo>.</mo> </mrow> </math>

in this embodiment, fig. 2 is the power consumption obtained by the optimal solution, the suboptimal solution and the fairness solution based on the D2D communication total reachable rate threshold. Wherein, the optimal scheme is the method of the embodiment; the suboptimal solution is a case of the method of the embodiment, namely, all cellular users adopt a base station communication mode; the fairness scheme is to divide the total reachable rate threshold requirement of D2D communication as equally as possible on each frequency band; fig. 3 is a power consumption based on an optimal solution, a sub-optimal solution and a fairness solution for D2D communication distance. As can be seen from fig. 2 and fig. 3, the performance of the present embodiment is much higher than that of the suboptimal scheme and the fairness scheme. Fig. 4 is a graph of average total power consumption of the system over a single frequency band for optimal and suboptimal solutions based on cellular user groups with increasing distances to base stations. The distance from the s-th cellular subscriber group to the base station is (50(s-1),50s) meters. The power consumption energy-saving percentage graph of the relay coordination scheme can be found, and the scheme of the embodiment can greatly reduce the total power consumption of the system on the frequency band where the cellular user group around the relay node is located.

The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes and modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention.

Claims (5)

1. A communication resource allocation method of a relay cooperative heterogeneous cellular network D2D is characterized by comprising the following specific steps:

step 1: obtainingWhereinIndicating that D2D communication is achieved in frequency band n when cellular user n adopts communication mode q (n)A maximum achievable rate threshold; wherein, cellular user n is the nth cellular user, and frequency band n is the nth frequency band; n is 1,2, …, N represents the total number of cellular users;

step 2: according toJudging whether the frequency spectrum resources selected by D2D communication can meet the system service quality requirement;

and step 3: allocation of reachable rate targets allocated on frequency band n by D2D communication when cellular user n adopts communication mode Q (n)And determining a communication mode q (n) of the cellular user n;

and 4, step 4: calculating the total transmission power P of the system^total。

2. The method for allocating communication resources in D2D in a relay cooperative heterogeneous cellular network according to claim 1, wherein the communication resources are obtained according to minimum reachable rate threshold requirements of cellular communication and D2D communication in a single frequency bandThe expression is as follows:

wherein,is composed ofThe corresponding SINR (signal to interference plus noise ratio),respectively indicating that the cellular user n adopts the communication mode Q (n) to lower the cellular link channel gain and the D2D linkChannel gain, link channel gain from a cellular user n to a D2D communication receiving end, and link channel gain from a D2D transmitting end to a cellular user n receiving end; q (n) {1,2}, q (n) ═ 1, q (n) ═ 2 denote that cellular user n employs the base station communication mode and the relay coordination mode, respectively, and it is assumed that cellular user n uses frequency band n;minimum reachable rate threshold for D2D communication on frequency band n when cellular user n adopts communication mode Q (n)Corresponding SINR, and the minimum achievable rate threshold of D2D communication on the frequency band n when the cellular user n adopts the relay coordination modeIs the minimum reachable rate threshold of D2D communication on the frequency band n when the cellular user n adopts the base station communication modeTwice as much as the amount of the first,

3. the method for allocating communication resources in a relay cooperative heterogeneous cellular network D2D as claimed in claim 2, wherein in step 2, the formula of the judgment criterion for judging whether the spectrum resources selected by D2D communication can meet the requirement of system service quality is as follows:

if the above formula is satisfied, the service quality requirement is satisfied; wherein,representing the minimum achievable rate threshold for D2D communication over frequency band n,representing the maximum achievable total achievable rate of D2D communication over all multiplexed N frequency bands,represents the total achievable rate threshold of the D2D communication over all the multiplexed N frequency bands;indicating that the maximum value in brackets is selected under different cellular communication modes q (n).

4. The method for allocating communication resources of a relay collaborative heterogeneous cellular network D2D according to claim 3, wherein the step 3 specifically includes the steps of:

step 3.1: initializing an initial communication mode q (n) for each cellular user, the initialization criteria of q (n) being:

step 3.2: initializing lambda₁And λ₂，λ₁、λ₂Respectively a smaller Lagrange multiplier and a larger Lagrange multiplier, and defining a weighting function w_Q(n),n：

Wherein λ represents a lagrange multiplier;

initializing lambda₁And λ₂The following criteria are satisfied:wherein,r (λ) represents the total achievable rate allocated by D2D communication over all N frequency bands at the value of λ;the achievable rate targets assigned for D2D communication in frequency band n, based on the cellular user n assuming cellular communication mode q (n), are variables for the lagrangian multiplier lambda,the expression of (a) is:

wherein,

represents the minimum SINR threshold value of the cellular user N on the frequency band N by adopting the communication mode Q (N), the superscript-1 represents the power of-1, N₀Representing system noise;in the cellular communication mode q (n) adopted for the cellular user n, the SINR target on the frequency band n allocated to D2D communication is a variable related to the lagrangian multiplier λ, and needs to satisfy:wherein,minimum achievable rate threshold over frequency band n for D2D communicationA corresponding SINR value;are respectively corresponding toAnd Q (n), the optimal transmit power for cellular users n, D2D users on band n,the expression of (a) is:

step 3.3: determining cellular user n achievable rate targetThe determination criteria of the following communication mode q (n) are:

i.e. cellular subscriber n is in correspondenceIs selected at a value of w_Q(n),nThe lowest value of the communication modes Q (n), in which

Step 3.4: circularly solving reachable velocity threshold targetAnd a communication mode q (n) of the cellular user n, the cycle criterion being:

if it isReturn to correspondingAnd go to step 4; otherwise, ifLet lambda₂λ and return to step 3.3; if it isLet lambda₁λ and return to step 3.3;

r (λ) represents the total achievable rate allocated by D2D communication over all N frequency bands at the value of λ; representing the precision of the dichotomy;the optimal reachable rate threshold assigned to D2D communication in frequency band n when cellular user n adopts communication mode q (n) is determined by lagrangian multiplier λ^*A variable of (d); lambda [ alpha ]^*Representing the optimal lagrangian multiplier obtained when the loop is stopped.

5. The method for allocating communication resources of D2D in relay cooperative heterogeneous cellular network according to claim 4, wherein P is P^totalFor the total system transmit power, the expression is:

wherein,andrespectively representing the optimal Lagrange multiplier lambda^*And q (n), the optimal transmit power for cellular users n, D2D users on frequency band n.