CN104219676A - Single station traffic based dynamic frequency reuse method for TD-LTE (time division long term evolution) - Google Patents

Abstract

The invention discloses a single station traffic based dynamic frequency reuse method for TD-LTE (time division long term evolution). The method includes: taking network single cell edge user peak load capacity or service provider or industry regulated single cell edge user peak handling capacity as a threshold value A, taking one-time bandwidth variation increased or decreased according to a service provider or industry regulated step length as B, taking a spectral bandwidth occupied by a180KH<z> single RB as graininess to randomly and dynamically distribute frequency spectrums, and carrying out bandwidth distribution as follows.

Description

The dynamic frequency multiplexing method of a kind of TD-LTE based on single station traffic carrying capacity

Technical field

The present invention relates to a kind of signal and communication field, the particularly a kind of TD-LTE dynamic frequency multiplexing method based on single station traffic carrying capacity.

Background technology

Existing LTE frequency reuse plan mainly contains partial frequency multiplexing (FFR), and soft-frequency reuse (SFR), and SFR is divided into again basic model SFR and enhancement mode SFR.

1, partial frequency multiplexing (FFR)

For LTE system, the access way of its unique OFDMA adopting, makes not interfere with each other between the user in this community, receives the more intense interference that comes from other communities for the user of cell edge.The core concept of partial frequency multiplexing is to treat with a certain discrimination in the user of center of housing estate and cell edge, for the user of center of housing estate, because it is closer apart from base station distance, channel condition is better, and itself is little to the interference of other communities, be on 1 multiplexing collection so can be distributed in frequency duplex factor as one.And for the user of cell edge, its serving BS apart from self is distant, and channel condition is poor, but the interference of its signal in same frequency for other communities is larger again, so be distributed in frequency duplex factor as one and be on 3 channeling collection, seen Fig. 1.

Fixed frequency multiplex mode can comprise following two kinds of modes:

(1) use 40MHz frequency spectrum, be divided into 4 10MHz frequency bands, as Fig. 2 distributes:

The actual usable spectrum in each community is 20MHz.Wherein Liang Ge community can be used continuous 20MHz bandwidth (f1+f2 community, f1+f3 community), and another community can only be used the 10MHz bandwidth (f1+f4 community) of 2 separation, and spectrum disposition mode is comparatively complicated.

(2) use 20MHz frequency spectrum, internal separation is 4 5MHz sub-bands, as Fig. 3 distributes:

Each community is under the frequency range of 20MHz, and cell edge weak signal region actual available bandwidth is 5MHz, and the actual usable spectrum in inner strong signaling zone, community is 10MHz.

2, soft-frequency reuse (SFR)

Soft-frequency reuse has been inherited the advantage of partial frequency multiplexing, adopts dynamic frequency duplex factor as one simultaneously, has improved the utilization ratio of frequency obviously.In soft-frequency reuse, all frequency ranges have been divided into two groups of subcarriers, and one group is called boss's carrier wave, and other one group is called auxiliary subcarrier.Boss's carrier wave can be in the use Anywhere of community, and auxiliary subcarrier can only be used at center of housing estate.Boss's carrier wave between different districts is mutually orthogonal, has effectively suppressed interference at cell edge, and auxiliary subcarrier is owing to only using at center of housing estate, disturbs each other littlely, can use identical frequency.

(1) basic model SFR

Under 20MHz bandwidth, be divided into 3 6.67MHz frequency bands as boss's carrier wave, for each one of 3 adjacent cell edges; Simultaneously each center of housing estate region is used 2/3 other frequency spectrum of this community, as Fig. 4:

In this manner, center of housing estate uses 2/3 usable spectrum, and cell edge uses 1/3 usable spectrum.

(2) enhancement mode SFR

Although soft-frequency reuse is for the inhibition of cell edge disturbed condition, and the flexible allocation of subcarrier has all had certain consideration, but its mutually orthogonal boss's carrier wave of distributing to different districts still can bring the wasting of resources to a certain degree, especially in the time that the traffic carrying capacity of cell edge is larger, can bring that frequency duplex factor as one between community increases, degradation consequence under the availability of frequency spectrum.The soft-frequency reuse scheme strengthening has been inherited the thought of traditional soft-frequency reuse, improves on its basis again, is mainly to have improved the problem of the wasting of resources that may bring in the time that traffic carrying capacity changes.

Under 20MHz frequency spectrum, be divided into 3 frequency bands as boss's carrier wave, 20MHz frequency band only uses at center of housing estate as auxiliary subcarrier simultaneously, as Fig. 5.

Not only the occupied bandwidth of f2, f3, f4 is dynamically adjusted according to the traffic carrying capacity of each cell edge region, and according to traffic carrying capacity size, each center of housing estate region usable spectrum also can be reached for 20MHz.

Modified model SFR adopts dynamic-configuration mode, need to understand the load information of peripheral cell, therefore needs to be used in conjunction with ICIC (Inter-Cell Interference Coordination) technology, just can reach good effect.

Summary of the invention

Goal of the invention: technical problem to be solved by this invention is need to adopt dynamic frequency allocation scheme for the actual conditions of LTE network design, but existing enhancement mode SFR too complex, need to coordinate between base station, the complexity of antenna for base station and the amount of calculation of scheduler are greatly increased, therefore need reasonable coordination spectrum efficiency and implementation complexity, proposition can dynamically be adjusted frequency spectrum according to network actual conditions, implementation complexity is the technical problem of relatively simple frequency reuse plan again, and the dynamic frequency multiplexing method of a kind of TD-LTE based on single station traffic carrying capacity is provided.

In order to solve the problems of the technologies described above, the invention discloses the dynamic frequency multiplexing method of a kind of TD-LTE based on single station traffic carrying capacity, with single Cell Edge User peak load amount of network, or single Cell Edge User peak throughput of operator or industry regulation is that threshold value is made as A, identify edge customer and the central user of community, the variable quantity that the step-length specifying with operator or industry increases or reduce bandwidth is made as B, for Cell Center User distributes all bandwidth, the bandwidth taking taking 180KHz single resource piece for Cell Edge User is granularity initial bandwidth of Random assignment within the scope of whole spectral bandwidth, carry out in accordance with the following steps allocated bandwidth:

Original allocation cell edge region user's bandwidth is B, increases successively bandwidth B after throughput meets following condition newly:

Edge customer throughput=A* η * (B*I/N),

Wherein I represents increases the coefficient of determination of bandwidth the i time, I=N/B, and I span is 2～10, N represents maximum bandwidth, and i is initially 1, i=1 increases the coefficient of determination of bandwidth for the first time, Cell Edge User 2B bandwidth altogether after increasing, i is the integer since 1, is (N-B)/B to the maximum; η is stressor, and load reaches after the peak throughput certain percentage of current bandwidth, the bandwidth of the newly-increased B in system Gei Gai community, η span 0.4～0.7;

In the time of edge customer throughput=A* η * ((N-B)/N), distribute whole maximum bandwidth N;

Wherein (N-B)/N represents the bandwidth ratio that a stage takies;

When edge customer throughput is reduced to less than while equaling A* η * (B*J/N), reduce after B bandwidth, edge customer has bandwidth J*B altogether.

Wherein J represents and reduces the coefficient of determination of bandwidth the j time, J=N/B, and J span is 2～10.

In the present invention, set the integral multiple that N is B.

Resource Block ResourceBlock, is called for short RB.

The principle of the invention is: at center, base station section, (this cell signal is better, the region less to other area interference) distributes to all frequency spectrums of user, to increase sector entire throughput.At base station section fringe region, (this cell signal is poor, the region serious to other area interference) dynamically adjust frequency spectrum according to the total business volume size of edge customer, the partial frequency spectrum of dynamic assignment is taking 180KHz (spectral bandwidth that single RB takies) as granularity Random assignment in whole spectral range, reduces presence of intercell interference with the less cost that realizes.Make network in the situation that business demand is higher, distribute more frequency spectrum, promote the peak throughput of heavy traffic demand community, promote user awareness; In the situation that business demand is less, distribute less frequency spectrum at network, reduce the interference to other community.

Beneficial effect: 1, dynamically adjust frequency spectrum

This programme can dynamically be adjusted frequency spectrum according to the total business volume of base station section fringe region, makes network in the situation that business demand is higher, distribute more frequency spectrum, promotes the peak throughput of heavy traffic demand community, promotes user awareness; In the situation that business demand is less, distribute less frequency spectrum at network, reduce the interference to other community.

2, adjust frequency spectrum Random assignment

The partial frequency spectrum of dynamic assignment is taking 180KHz (spectral bandwidth that single RB takies) as granularity Random assignment in whole spectral range, reduces presence of intercell interference with the less cost that realizes.

3, implementation complexity is low

Compared with needing many base stations Coordination Treatment with enhancement mode SFR, this programme only need to be considered the traffic needs of this community, does not need to consider the network condition of adjacent cell, and therefore this programme implementation complexity is lower, less to the change of network.

4, improve network capacity

In this programme, cell business volume demand can be considered in each community, distributes as far as possible more frequency spectrum in traffic needs Gao community, to meet consumers' demand, therefore can significantly improve whole net network capacity, promotes user awareness.

5, existing network applicability is strong

This programme is realized simple, and the suitable any region of existing network that is applied to is particularly useful for that the base station station spacings such as CBD/ dense city are less, the region of serious interference.Can well solve and improve spectrum efficiency and reduce the contradiction between implementation complexity.

6, network O&M is convenient

This programme is realized simple, and each base station only needs to collect, monitor traffic carrying capacity in this community, does not need to work in coordination with between base station, under the network change conditions such as newly-increased base station, resettlement base station, does not need to revise any parameter, and network O&M is very convenient.

Brief description of the drawings

Below in conjunction with the drawings and specific embodiments, the present invention is done further and illustrated, above-mentioned and/or otherwise advantage of the present invention will become apparent.

Fig. 1 is prior art partial frequency multiplexing schematic diagram.

Fig. 2 is prior art partial frequency multiplexing dividing mode one schematic diagram.

Fig. 3 is prior art partial frequency multiplexing dividing mode two schematic diagrames.

Fig. 4 is prior art basic model soft-frequency reuse schematic diagram.

Fig. 5 is prior art enhancement mode soft-frequency reuse schematic diagram.

Fig. 6 is the flow chart of the inventive method

Fig. 7 is dynamic frequency multiplexing scheme (omni-base station) schematic diagram that the present invention is based on single BTS service amount.

Fig. 8 is dynamic frequency multiplexing scheme (three sector base stations) schematic diagram that the present invention is based on single BTS service amount.

Fig. 9 is the dynamic frequency multiplexing method schematic diagram based on single BTS service amount.

Embodiment

The invention discloses the dynamic frequency multiplexing method of a kind of TD-LTE based on single station traffic carrying capacity, estimate that network list carrier frequency bandwidth is N, cell structure can be omni-base station or three sector base stations, sees respectively schematic diagram 6 and Fig. 7.

Center of housing estate and cell edge confining method: the threshold value using the far point index in the generally acknowledged near point of industry, mid point, far point as cell edge, or the RS-SINR/RSRP numerical value of specifying using operator is as threshold value M, and the region that signal index is less than threshold value is cell edge.In the time that user's index of correlation changes (central user index is greater than threshold value/edge customer index and is less than threshold value), need through lag time T1, within the T1 time, user's index remains at and changes in rear scope, and system is by corresponding user property change.

The calculating of traffic carrying capacity and definition: with single Cell Edge User peak load amount of network, or single Cell Edge User peak throughput of operator/industry regulation is that threshold value is made as A, a variable quantity that increases/reduce bandwidth taking the suitable step-length of operator/industry regulation is made as B (suggestion N is as the integral multiple of B), and allocated bandwidth formula is as follows:

System original allocation fringe region user's bandwidth is B, and bandwidth B is taking 180KHz (spectral bandwidth that single RB takies) as granularity Random assignment in whole spectral range,, after meeting following condition, throughput increases successively bandwidth B newly:

As edge customer throughput=A* η * (B*I/N)

wherein I represents increases the coefficient of determination (I=N/B, suggestion span is 2-10) of bandwidth the i time, is initially 1, i=1 increases the coefficient of determination of bandwidth for the first time, increases back edge user 2B bandwidth altogether, and i is integer, since 1, be (N-B)/B to the maximum;

η is stressor, and load reaches after the peak throughput certain percentage of current bandwidth, the bandwidth of the newly-increased B in system Gei Gai community, suggestion span 0.4-0.7.

In the time of edge customer throughput=A* η * ((N-B)/N), distribute whole N bandwidth;

wherein (N-B)/N represents the bandwidth ratio that a stage takies;

In the time that edge customer throughput reduces, decision threshold is same as above.While being less than A* η * (B*J/N), reduce after B bandwidth, have altogether bandwidth J*B.Wherein J represents and reduces the coefficient of determination (J=N/B, suggestion span is 2-10) of bandwidth the j time.

When throughput meets after correlated condition, need to pass through lag time T2, in T2 time inward flange region, user throughput demand meets after correlated condition all the time, and system is that fringe region user increases/reduce B bandwidth.

System processing unit: TD-LTE system is used for the system module into fringe region user assignment bandwidth, can increase corresponding module in base station newly, also can be integrated in BBU equipment.

Scheme running: when initial launch, system processing unit is determined Cell Center User and Cell Edge User according to cell edge confining method, distributes whole N bandwidth to Cell Center User, Cell Edge User Random assignment B bandwidth.In the time that Cell Edge User aggregate demand bandwidth continues to exceed A* η * (B/N) within the T2 time, system processing unit is to Cell Edge User Random assignment 2B bandwidth; In the time that Cell Edge User aggregate demand bandwidth continues to exceed A* η * (B*I/N) within the T2 time, system processing unit is to Cell Edge User Random assignment B* (1+i) bandwidth; By that analogy until system processing unit distributes whole N bandwidth to Cell Edge User.In the time that Cell Edge User aggregate demand bandwidth continues lower than A* η * (B*I/N) within the T2 time, system processing unit distributes B*I bandwidth to Cell Edge User.When certain Cell Edge User is when within the T1 time, RS-SINR/RSRP continues to be greater than M, this user property is become Cell Center User by system, is always the whole N bandwidth of this user assignment, and the central area user area edge user procedures that diminishes is similar.

Embodiment

The present invention at center, base station section (this cell signal is better, the region less to other area interference) distribute to all frequency spectrums of user, to increase sector entire throughput.At base station section fringe region, (this cell signal is poor, the region serious to other area interference) dynamically adjust frequency spectrum according to the total business volume size of edge customer, the partial frequency spectrum of dynamic assignment is taking 180KHz (spectral bandwidth that single RB takies) as granularity Random assignment in whole spectral range, reduces presence of intercell interference with the less cost that realizes.Make network in the situation that business demand is higher, distribute more frequency spectrum, promote the peak throughput of heavy traffic demand community, promote user awareness; In the situation that business demand is less, distribute less frequency spectrum at network, reduce the interference to other community.

Suppose that certain all base station of operator's TD-LTE network adopts three sector pattern networkings, its spectral bandwidth is 20MHz; The threshold value defining as Cell Edge User using RS-SINR=0dB; Lag time T1 is 5 seconds; Single Cell Edge User peak throughput is that threshold value A is 10Mbps; The step-length that increases/reduce bandwidth is 5MHz; Stressor η is 0.5; Lag time T2 is 10 seconds; System processing unit is integrated in BBU.

Scheme running is as follows, with reference to figure 8:

when initial launch, BBU distributes 20MHz bandwidth, Cell Edge User (RS-SINR<0dB) Random assignment 5MHz bandwidth to Cell Center User (RS-SINR>=0dB);

in the time that Cell Edge User aggregate demand continues to exceed 1.25Mbps in 10s, BBU distributes 10MHz bandwidth to Cell Edge User;

in the time that Cell Edge User aggregate demand continues to exceed 2.5Mbps in 10s, BBU distributes 15MHz bandwidth to Cell Edge User;

in the time that Cell Edge User aggregate demand continues to exceed 3.75Mbps in 10s, BBU distributes 20MHz bandwidth to Cell Edge User;

in the time that Cell Edge User aggregate demand continues lower than 5* (I/4) Mbps in 10s, BBU distributes 5*IMHz bandwidth to Cell Edge User;

when the RS-SINR of certain Cell Edge User value continues to be greater than 0dB in 5s, this user property is become Cell Center User by BBU, is always this user assignment 20MHz bandwidth;

When the RS-SINR of certain Cell Center User value continues to be less than 0dB in 5s, this user property is become Cell Edge User by BBU, is according to circumstances this user assignment 5*IMHz bandwidth.

Existing relevant soft-frequency reuse algorithm is all comparatively complicated, needs to coordinate between base station, has greatly increased the complexity of antenna for base station and the amount of calculation of scheduler, implements difficulty larger, therefore not yet scale use soft-frequency reuse technology of existing network.The inventive method adopts Random assignment technology, realizes cost and has reduced the interference of minizone with less.

Through simulation calculating checking, adopt after the present embodiment dynamic frequency multiplexing method, Cell Edge User average throughput ratio improves 24.7% when proportion is not multiplexing, and the RS-SINR mean value of Cell Edge User improves 3.7dB.

In Fig. 9, under 20MHz frequency spectrum, divide 20MHz frequency band and only use at center of housing estate as auxiliary subcarrier, divide variable 0-20MHz frequency band simultaneously and use Anywhere in community as boss's carrier wave.

The occupied bandwidth of f2 is dynamically adjusted according to the total business volume demand of each base station section fringe region, traffic carrying capacity is higher, the occupied bandwidth of f2 is larger, the bandwidth of f2 is dynamic assignment in 20MHz bandwidth, the step-length that each dynamic assignment increases/reduces is 5MHz, the bandwidth of dynamic assignment is that the spectral bandwidth taking taking the mono-RB of 180KHz is granularity Random assignment in whole spectral range, and the adaptive-bandwidth scope of f2 is 0-20MHz.

The invention provides the dynamic frequency multiplexing method of a kind of TD-LTE based on single station traffic carrying capacity; method and the approach of this technical scheme of specific implementation are a lot; the above is only the preferred embodiment of the present invention; should be understood that; for those skilled in the art; under the premise without departing from the principles of the invention, can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.In the present embodiment not clear and definite each part all available prior art realized.

Claims (2)

1. the TD-LTE dynamic frequency multiplexing method based on single station traffic carrying capacity, it is characterized in that, taking single Cell Edge User peak load amount of network or single Cell Edge User peak throughput as threshold value A, identify Cell Edge User and Cell Center User, the variable quantity that the step-length specifying with operator or industry increases or reduce bandwidth is made as B; For Cell Center User distributes all bandwidth, the bandwidth taking taking 180KHz single resource piece for Cell Edge User is granularity initial bandwidth of Random assignment within the scope of whole spectral bandwidth, specifically carries out in accordance with the following steps allocated bandwidth:

Original allocation cell edge region user's bandwidth is B, increases successively bandwidth B after throughput meets following condition newly:

Edge customer throughput=A* η * (B*I/N),

Wherein I represents increases the coefficient of determination of bandwidth the i time, I=N/B, and I span is 2～10, N represents maximum bandwidth, and i is initially 1, i=1 increases the coefficient of determination of bandwidth for the first time, Cell Edge User 2B bandwidth altogether after increasing, i is the integer since 1, is (N-B)/B to the maximum; η is stressor, and load reaches after the peak throughput certain percentage of current bandwidth, the bandwidth of the newly-increased B in system Gei Gai community, η span 0.4～0.7;

In the time of edge customer throughput=A* η * ((N-B)/N), distribute whole maximum bandwidth N;

Wherein (N-B)/N represents the bandwidth ratio that a stage takies;

When edge customer throughput is reduced to less than while equaling A* η * (B*J/N), reduce after B bandwidth, edge customer has bandwidth J*B altogether;

Wherein J represents and reduces the coefficient of determination of bandwidth the j time, J=N/B, and J span is 2～10.

2. the dynamic frequency multiplexing method of a kind of TD-LTE according to claim 1 based on single station traffic carrying capacity, is characterized in that, the integral multiple that setting N is B.