CN102970758B - Straight-through self-adaptive resource distribution method for cellular communication system terminal - Google Patents

Abstract

The invention discloses a straight-through self-adaptive resource distribution method for a cellular communication system terminal, which is specifically a resource distribution method for device-to-device (D2D) communication based on an orthogonal frequency division multiplexing system. Based on the characteristic of low transmission power of D2D users, and with consideration of the multiplex of same resources of two groups of D2D pairs, when cellular user resources are distributed to the D2D pairs, path attenuation, interference channel gains of cellular users on the D2D users and channel gains between the D2D users are considered at the same time, so that the resources with maximum equivalent channel gains are distributed to the matched D2D pairs in a self-adaptive manner so as to maximize a throughput capacity. The straight-through self-adaptive resource distribution method has the advantages that the capacity of a D2D system can be greatly improved, and an algorithm is relatively simple.

Description

Cellular communication system terminal leads directly to adaptive resource allocation method

Technical field

The present invention is a kind of based on the D2D(device-to-device under ofdm system) resource allocation methods that communicates, belong to the resource allocation techniques field in mobile communication.

Background technology

Resourse Distribute is the key of mobile communication system energy proper communication.Because the frequency spectrum resource that can be used for mobile communication is very limited, just need to utilize frequency spectrum resource more efficiently, D2D technology is arisen at the historic moment.From present D2D resource allocation methods, most methods is all often organize the frequency spectrum resource of D2D to multiplexing all multiplexing different phone user, almost do not mention the method for two or more sets D2D to multiplexing same cellular user resources, and adopt two or more sets D2D can improve spectrum efficiency greatly to multiplexing identical phone user's resource; Simultaneously for D2D is to selecting all resources that can be not limited to single phone user during multiplexing resource, may alternate betwwen good and bad in these resources, restriction may be caused to D2D communication if all multiplexing.So the resource selected for D2D user is good from each phone user is multiplexing to carry out, is namely thought of as starting point with subcarrier instead of the diversity gain of the capable and multi-user of the He Ne laser of channel can better be utilized with phone user.When Resourse Distribute, we adopt a kind of adaptive sub-carrier wave distribution method, distribute to the maximum user of equivalent channel gain in the above by each subcarrier, equivalent channel be here by D2D between channel, interference channel, interference power is unified considers to obtain.D2D power system capacity is improve significantly based on foregoing.

Summary of the invention

Technical problem: the object of this invention is to provide a kind of cellular communication system terminal and lead directly to adaptive resource allocation method, mainly for a fairly large number of D2D to the situation will carrying out Resourse Distribute, reduce phone user to the interference of D2D user, improve power system capacity and the availability of frequency spectrum of D2D system greatly.

Technical method: cellular communication system terminal of the present invention leads directly to adaptive resource allocation method and is:

1), inner ring and outer shroud (adopting D2D pattern that better performance can be obtained at outer shroud) is divided into according to distance areas by little;

2) region, by outer shroud being divided into even number equal, is just defined as one group of region of mating to two regions in the center of circle;

3), in two regions of coupling, look for a pair D2D to one group of D2D couple as coupling respectively at random, as Fig. 2;

4), base station calculates equivalent channel gain between D2D user to D2D to the interference channel gain of user, channel gain between path fading and D2D user according to current time phone user wherein H _dfor the equivalent channel gain between D2D user, h _dfor the actual channel gain between D2D user, P _{i, CiD}for phone user is to the interference power of D2D user, h _ciDfor the interference channel gain between phone user and D2D user;

5), make N, V is used for representing and often organizes D2D to the number of subcarriers of distributing and equivalent channel gain, and its initial value is set to 0;

6), all assignable subcarriers are followed successively by the D2D couple of one group of coupling that it selects average equivalent channel gain on this subcarrier maximum, by this sub carries allocation to the D2D couple of this group coupling, and the item corresponding to N is added 1 until it meets required sub-carrier number, be no longer then its allocation of subcarriers, and record the equivalent channel gain be assigned to V;

7), step 6 is repeated) until by complete for all sub carries allocation;

This cellular system terminals leads directly to self adaptation pairing resource allocation methods and greatly improves power system capacity and spectrum efficiency by allowing the D2D of zones of different to the multiplexing identical phone user's resource of coupling, consider to avoid bad subcarrier with subcarrier when Resources allocation, and consider with equivalent channel more to meet the requirement improving D2D user capacity.Wherein two groups of D2D can be applied directly to the multiplexing identical phone user's resource of coupling a lot distributing in the method for different phone user's resource for often organizing D2D to user, obtaining the gain in great performance.

Beneficial effect:

1, introduce the concept of equivalent channel gain, consider the factor affecting D2D power system capacity comprehensively, avoid considering separately interference power, interference channel gain, effectively improve D2D power system capacity.

2, adopting for subcarrier is the Resourse Distribute of unit, avoids and the frequency spectrum resource for D2D user's condition difference is distributed to D2D user.

3, adopt the D2D of two groups of zoness of different to multiplexing identical phone user's resource, control the capacity and the spectrum efficiency that greatly improve D2D system between D2D pair while interference.

What the present invention proposed two groups of D2D can be applied directly to the multiplexing identical phone user's resource of coupling is much often organize D2D to distribute in the method for different phone user's resource to user, obtains the gain in great performance.

The present invention mainly considers how to lead directly in resource allocation process in cellular system terminals to reduce the interference of phone user to D2D user, improves D2D power system capacity.

Accompanying drawing explanation

Fig. 1 is system model figure, supposes to adopt the user of D2D pattern to be evenly distributed on the outer shroud of community, and phone user's Random assignment is in community.

Fig. 2 is that D2D of the present invention is to coupling schematic diagram.

Fig. 3 is the flow chart of resource allocation methods.

Embodiment

Suppose that the sub-carrier number that an OFDM symbol comprises is M, phone user and the right quantity of D2D are respectively N _cand N _d, D2D user directly can communicate under the coordination of base station, and the resource of D2D user multiplexing phone user when communicating.

We suppose that the power that all phone users arrive base station all controls at identical horizontal P _cB, namely

$P_{\mathrm{CB}}=P_{\mathrm{Ci}}\·{\left(d_{\mathrm{Ci}}\right)}^{-a},\∀i$ [formula one]

P _cBfor constant, P _cibe the transmitting power of i-th phone user, d _cifor this phone user is to the distance of base station.So just can be write as the interference power of D2D by phone user

$P_{I,\mathrm{CiD}}=P_{\mathrm{Ci}}{\left(d_{\mathrm{CiD}}\right)}^{-a},\∀i$ [formula two]

D _ciDfor phone user is to the distance of D2D reception user, and D2D is limited in δ to the interference power of base station by strict _b, i.e. P _d(d _dB) ^-a/ P _cB≤ δ _b, to guarantee to produce interference P to base station _dfor the transmitting power of D2D user, d _dBfor D2D user is to the distance of base station.The channel capacity of D2D user can be obtained by shannon formula:

$C_d={\log }_2(1+\frac{P_D\·{\left(d_D\right)}^{-a}\·h_d}{P_{I,\mathrm{CiD}}\·h_{\mathrm{CiD}}+P_{D^{\′}}{\left(d_{{\mathrm{dd}}^{\′}}\right)}^{-a}{h}_{d^{\′}d}+n_0})$ [formula three]

P _d'for another of multiplexing same cellular user resources is to the transmitting power of D2D user, h _dd'be two to the channel gain between the D2D user of multiplexing same cellular user resources, d _dd'distance between being two pairs D2D pair of multiplexing same asset, n ₀for the one-sided power spectrum density of noise.Be P adopt the condition of maximum transmission power D2D user under _d=(d _dB) ^aδ _bp _cB, make P _cB=cn ₀, c is constant, then can obtain the ratio of interference power between D2D pair and noise power;

$\frac{P_D\·{\left(d_{{\mathrm{DD}}^{\′}}\right)}^{-a}}{n_0}=\frac{{(d_{\mathrm{DB}}/d_{{\mathrm{DD}}^{\′}})}^a\·{\mathrm{\δ}}_B\·P_{\mathrm{CB}}}{n_0}=\frac{{(d_{\mathrm{DB}}/d_{{\mathrm{DD}}^{\′}})}^a\·{\mathrm{\δ}}_B\·c\·n_0}{n_0}={(d_{\mathrm{DB}}/d_{{\mathrm{DD}}^{\′}})}^a\·{\mathrm{\δ}}_B\·c$ [formula four]

And this formula is be easy to reach the situation much smaller than 1 by suitably feasible value of adjusting the distance.

Concrete distribution method performing step is as follows:

1. divide into inner ring and outer shroud (adopting D2D pattern that better performance can be obtained at outer shroud) by base station by little;

2. the region being divided into even number equal outer shroud, is just defined as one group of region of mating, as Fig. 2 to two regions in the center of circle;

3. base station looks for a pair D2D to one group of D2D couple as coupling respectively at random in two regions of coupling;

4. base station calculates equivalent channel gain between D2D user to D2D to the interference channel gain of user, channel gain between path fading and D2D user according to current time phone user wherein H _drepresent the equivalent channel gain between D2D user, h _drepresent the actual channel gain between D2D user, P _{i, CiD}represent that phone user is to the interference power of D2D user, h _ciDrepresent the interference channel gain between phone user and D2D user;

5. initialization N and V, be used for respectively representing and often organize D2D to the number of subcarriers of distributing and equivalent channel gain, its initial value is set to 0;

6. all assignable subcarrier base stations are followed successively by the D2D couple of one group of coupling that it selects average equivalent channel gain on this subcarrier maximum, by this sub carries allocation to the D2D couple of this group coupling, and the item corresponding to N is added 1 until it meets required sub-carrier number, be no longer then its allocation of subcarriers, and record the equivalent channel gain be assigned to V;

7. repeat step 6 until by complete for all sub carries allocation;

The average size of D2D system is finally calculated according to channel capacity formula.This invention can greatly improve D2D user capacity relative to conventional allocation method.

This method is a kind of D2D resource allocation methods of new high efficiency in a word, its objective is and improves D2D power system capacity and the availability of frequency spectrum, reduces phone user to the interference of D2D user, thus meets the requirement of D2D user's high data rate traffic.

Claims (1)

1. cellular communication system terminal leads directly to adaptive resource allocation method, it is characterized in that the method for this Resourse Distribute is:

1), according to distance divide into inner ring and outer shroud by little, adopt D2D pattern to obtain better performance at outer shroud;

2) region, by outer shroud being divided into even number equal, is just defined as one group of region of mating to two regions in the center of circle;

3), in two regions of coupling, look for a pair D2D to one group of D2D couple as coupling respectively at random;

4), base station calculates equivalent channel gain between D2D user to D2D to the interference channel gain of user, channel gain between path fading and D2D user according to current time phone user wherein H _dfor the equivalent channel gain between D2D user, h _dfor the actual channel gain between D2D user, P _{i, CiD}for phone user is to the interference power of D2D user, h _ciDfor the interference channel gain between phone user and D2D user;

5), make N, V is used for representing and often organizes D2D to the number of subcarriers of distributing and equivalent channel gain, and its initial value is set to 0;

6), all assignable subcarriers are followed successively by the D2D couple of one group of coupling that it selects average equivalent channel gain on this subcarrier maximum, by this sub carries allocation to the D2D couple of this group coupling, and the item corresponding to N is added 1 until it meets required sub-carrier number, be no longer then its allocation of subcarriers, and record the equivalent channel gain be assigned to V;

7), step 6 is repeated) until by complete for all sub carries allocation.