CN102970758A - 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

The 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 the ofdm system) communication resource allocation methods, belong to the resource allocation techniques field in the mobile communication.

Background technology

It is the key of mobile communication system energy proper communication that resource is distributed.Because it is very limited to can be used for the frequency spectrum resource of mobile communication, just need to utilize more efficiently frequency spectrum resource, the D2D technology is arisen at the historic moment.From present D2D resource allocation methods, most methods all is every group of D2D to multiplexing all frequency spectrum resources of multiplexing different phone user, almost do not mention two or more sets D2D to the method for multiplexing same cellular user resources, and adopt two or more sets D2D can improve greatly spectrum efficiency to multiplexing identical phone user's resource; In all resources that can be not limited to single phone user for D2D when selecting multiplexing resource, may alternate betwwen good and bad in these resources simultaneously, if all multiplexingly may cause restriction to D2D communication.So select from each phone user and to carry out multiplexingly for the good resource of D2D user, namely be thought of as starting point rather than can better utilize the frequency of channel to select row and multi-user's diversity gain with the phone user with subcarrier.We adopt a kind of adaptive sub-carrier wave distribution method when resource is distributed, be about to each subcarrier and distribute to the user of equivalent channel gain maximum in the above, the equivalent channel here be with the channel between D2D, interference channel, interference power unified consider resulting.Thereby improved significantly the D2D power system capacity based on foregoing.

Summary of the invention

Technical problem: the purpose of this invention is to provide the straight-through adaptive resource allocation method of a kind of cellular communication system terminal, the situation of distributing carrying out resource mainly for a fairly large number of D2D, reduce the phone user to D2D user's interference, improve greatly D2D system of systems capacity and the availability of frequency spectrum.

Technical method: the straight-through adaptive resource allocation method of cellular communication system terminal of the present invention is:

1), according to distance areas with little interior ring and the outer shroud (adopting the D2D pattern can obtain better performance at outer shroud) divided into;

2) the one group of zone that, outer shroud is divided into the zone that even number equates, is defined as mating over against two zones in the center of circle;

3), in two zones of coupling, look at random respectively a pair of D2D to one group D2D pair of the conduct coupling, such as Fig. 2;

4), the base station is calculated equivalent channel gain between D2D user to D2D to the channel gain between user's interference channel gain, path fading and D2D user according to the current time phone user

H wherein _dBe the equivalent channel gain between D2D user, h _dBe the gain of the actual channel between D2D user, P _{I, CiD}Be the interference power of phone user to D2D user, h _CiDBe the gain of the interference channel between phone user and D2D user;

5), make N, V be used for representing number of subcarriers and the equivalent channel gain of every group of D2D to distributing, its initial value is made as 0;

6), be followed successively by one group of D2D pair of mating that it is chosen in average equivalent channel gain maximum on this subcarrier for all assignable subcarriers, this subcarrier is distributed to D2D pair that this group is mated, and add 1 until it satisfies desired sub-carrier number with N is corresponding, then no longer be its allocation of subcarriers, and record the equivalent channel gain that is assigned to V;

7), repeating step 6) until all subcarriers are assigned;

The straight-through self adaptation pairing of this cellular system terminals resource allocation methods is by allowing the D2D of zones of different improve greatly power system capacity and spectrum efficiency to mating multiplexing identical phone user's resource, when Resources allocation, consider to avoid bad subcarrier with subcarrier, and considered more can meet the requirement that improves the D2D user capacity with equivalent channel.The two groups of D2D that allow wherein can be applied directly to much on the method for every group of D2D to the different phone user's resources of user assignment to mating multiplexing identical phone user's resource, obtain the gain on the great performance.

Beneficial effect:

1, introduce the concept of equivalent channel gain, considered affect the factor of D2D power system capacity comprehensively, avoid considering separately that interference power, interference channel gain, Effective Raise the D2D power system capacity.

2, adopting for subcarrier is the resource distribution of unit, has avoided and will distribute to D2D user for the poor frequency spectrum resource of D2D user's condition.

3, the D2D that adopts two groups of zoness of different is to multiplexing identical phone user's resource, improved greatly capacity and the spectrum efficiency of D2D system when having controlled D2D to interference.

The present invention proposes allows two groups of D2D can be applied directly to much on the method for every group of D2D to the different phone user's resources of user assignment to mating multiplexing identical phone user's resource, obtains the gain on the great performance.

The present invention mainly considers how to reduce the phone user to D2D user's interference in the straight-through resource allocation process of cellular system terminals, improve the D2D power system capacity.

Description of drawings

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

Fig. 2 is that D2D of the present invention is to the 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, the quantity that phone user and D2D are right is respectively N _CAnd N _D, D2D user can directly communicate under the coordination of base station, and D2D user multiplexing phone user's when communication resource.

We suppose that the power that all phone users arrive the base station all is controlled at identical horizontal P _CB, namely

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

P _CBBe constant, P _CiBe i phone user's transmitting power, d _CiBe the distance of this phone user to the base station.Just can be write as the interference power of D2D by the phone user so

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

d _CiDBe that the phone user receives user's distance to D2D, and D2D to the interference power of base station by the strict δ that is limited in _B, i.e. P _D(d _DB) ^-a/ P _CB≤ δ _B, disturb P to guarantee can not produce the base station _DBe D2D user's transmitting power, d _DBBe the distance of D2D user to the base station.Can be got D2D user's channel capacity 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'Be another transmitting power to D2D user of multiplexing same cellular user resources, h _Dd'Be the channel gain between the D2D user of two pairs of multiplexing same cellular user resources, d _Dd'Be multiplexing same asset two couples of D2D to distance, n ₀One-sided power spectrum density for noise.Adopting under the condition of maximum transmission power D2D user is P _D=(d _DB) ^aδ _BP _CB, make P _CB=cn ₀, c is constant, then can get D2D to interference power and the ratio of 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 what to be easy to reach much smaller than 1 situation by the suitable feasible value of adjusting the distance.

Concrete distribution method performing step is as follows:

By the base station with little interior ring and the outer shroud (adopting the D2D pattern can obtain better performance at outer shroud) divided into;

2. outer shroud is divided into the zone that even number equates, the one group of zone that is defined as mating over against two zones in the center of circle is such as Fig. 2;

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

4. the base station is calculated equivalent channel gain between D2D user to D2D to the channel gain between user's interference channel gain, path fading and D2D user according to the current time phone user

H wherein _dEquivalent channel gain between expression D2D user, h _dActual channel gain between expression D2D user, P _{I, CiD}The expression phone user is to D2D user's interference power, h _CiDInterference channel gain between expression phone user and D2D user;

5. initialization N and V are used for respectively representing number of subcarriers and the equivalent channel gain of every group of D2D to distributing, and its initial value is made as 0;

6. be followed successively by one group of D2D pair of mating that it is chosen in average equivalent channel gain maximum on this subcarrier for all assignable subcarrier base stations, this subcarrier is distributed to D2D pair that this group is mated, and add 1 until it satisfies desired sub-carrier number with N is corresponding, then no longer be its allocation of subcarriers, and record the equivalent channel gain that is assigned to V;

7. repeating step 6 is until assign all subcarriers;

Calculate at last the average size of D2D system according to channel capacity formula.This invention can greatly improve the D2D user capacity with respect to the conventional allocation method.

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

Claims (1)

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

1), will be little divides into interior ring and outer shroud (can obtain better performance in outer shroud employing D2D pattern) according to distance, such as Fig. 1;

2) the one group of zone that, outer shroud is divided into the zone that even number equates, is defined as mating over against two zones in the center of circle;

3), in two zones of coupling, look at random respectively a pair of D2D to one group D2D pair of the conduct coupling, such as Fig. 2;

4), the base station is calculated equivalent channel gain between D2D user to D2D to the channel gain between user's interference channel gain, path fading and D2D user according to the current time phone user

H wherein _dBe the equivalent channel gain between D2D user, h _dBe the gain of the actual channel between D2D user, P _{I, CiD}Be the interference power of phone user to D2D user, h _CiDBe the gain of the interference channel between phone user and D2D user;

5), make N, V be used for representing number of subcarriers and the equivalent channel gain of every group of D2D to distributing, its initial value is made as 0;

6), be followed successively by one group of D2D pair of mating that it is chosen in average equivalent channel gain maximum on this subcarrier for all assignable subcarriers, this subcarrier is distributed to D2D pair that this group is mated, and add 1 until it satisfies desired sub-carrier number with N is corresponding, then no longer be its allocation of subcarriers, and record the equivalent channel gain that is assigned to V;

7), repeating step 6) until all subcarriers are assigned.

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