CN102158321A - Method for distributing power and choosing antenna in distributed type MIMO (multiple input multiple output) system and capable of increasing power efficiency of mobile communication system - Google Patents

Abstract

The invention discloses a method for distributing power and choosing an antenna in a distributed type MIMO (multiple input multiple output) system and capable of increasing power efficiency of a mobile communication system, and the method comprises the following steps: 1) utilizing a receiving terminal to periodically detect the large-scale channel fading information in the distributed type MIMO mobile communication system and feed the information back to a transmitting terminal; 2) carrying out filling power distribution among ports by a base station according to the received large-scale channel fading information; and 3) distributing equal power to all the ports according to the power distributing result received by each port, wherein the process of distributing the power and quickly choosing the antenna each time is finished by repeating the third step in each running period. By using the method for distributing the power and choosing the antenna in the distributed type MIMO system provided by the invention, the power efficiency of the mobile communication system is increased, the antenna-choosing and switching method for a multi-antenna mobile communication system is improved, and the mobile demand on the mobile communication system is ensured. The main task of an algorithm is to calculate the filling power distribution among the ports. The power distribution is based on the large-scale channel fading information, so the complexity in the actual system running process is lower.

Description

Power division and antenna selecting method in a kind of distributed MIMO system that can improve the mobile communication system power efficiency

Technical field

The present invention relates to the method that base station transmitting power distributes and antenna resource is allocated in the wireless mobile communications field, belong to RRM research field in the mobile communication system.

Background technology

Along with the extensive use of MIMO technology in mobile communication system, centralized multiaerial system, distributed multi-antenna system have become typical wireless network architecture in the mobile communication system.In order to use many antenna resource in the mobile communication system effectively, adopt between the centralized or spaced antenna in system coordination technique improve system spectrum utilance and power little, reasonably place many antennas and form the midsequent antenna systems and improve various novel wireless network architectures such as wireless signal coverage with higher power efficiency and also continue to bring out at the management and the dispatching method of antenna resource.Wherein, reasonably design antenna resource system of selection efficient in the mobile communication system running, low complex degree and become the inevitable requirement of RRM.

Traditional mimo system is called centralized mimo system again, it is based on traditional honeycomb, the concentrated place that is placed on of a plurality of antennas that adopt the MIMO technology, only require the spacing between each antenna to be equal to or greater than 1/2 signal wavelength, so that make that the right small scale decline of each a receipts/antenna is uncorrelated and obtain corresponding diversity gain.But this traditional centralized mimo system often exists so-called " shadow region " or " communication dead angle ", i.e. the antenna zone that can't cover owing to concentrate to place, and signal fadeout is fairly obvious even can have influence on normal communication in these zones.In addition, the method that conventional cellular systems increases spectrum efficiency mainly comprises sectorization and cell splitting, promptly towards many sectors, Microcell and mixed cell direction develop.But this can not be from dealing with problems in essence, and cell splitting can not unrestrictedly go on.Along with diminishing of sub-district area, can bring problems such as, system interference increase frequent more, frequency planning complexity, cost raising such as switching.For example be reduced to originally 1/2 the time when radius of society, required number of base stations will be original 4 times, causes the sub-district switching rate to increase greatly, and system complexity and cost also are exponential rising.The 3G system still adopts honeycomb at present, can reach transmission rate and the big power system capacity of 2Mbps.The design speed of 4G estimates that up to 100Mbps number of users also exceeds an order of magnitude than 3G system.Therefore, the 4G wireless access network will be difficult to satisfy simultaneously with rational cost the requirement of two-forty/big capacity and high coverage rate if continue to use traditional honeycomb.So the 4G Access Network must improve or adopt new structure to honeycomb.Under this background, traditional centralized mimo system will no longer be fit to such network topology structure.

Traditional antenna selecting method is mainly according to emission in the radio channel state choice set Chinese style multiaerial system of each antenna with accept antenna with the quantity that reduces radio frequency unit with improve method such as spatial correlation energy, in the distributed network structure that can't be applied to be made of a plurality of antennas difference laying methods.

Summary of the invention

Technical problem: the purpose of this invention is to provide power division and antenna selecting method in a kind of distributed MIMO system that can improve the mobile communication system power efficiency, it can satisfy transmit power allocations in many antenna mobile communication systems, day line options and portable terminal handoff algorithms fast, simple requirement.

Technical scheme is as follows:

Power division and antenna selecting method in a kind of distributed MIMO system that can improve the mobile communication system power efficiency may further comprise the steps:

The first step: receiving terminal is periodically measured the large scale channel fading information in the distributed MIMO mobile communication system, and this large scale channel fading feedback information is returned transmitting terminal;

Second step: the base station is carried out water injection power according to the large scale channel fading information that receives and is distributed between each port;

The 3rd step:, on each port, carry out constant power and distribute according to the water injection power allocation result that each port obtains;

Each power configuration and the quick selection course of antenna are to repeat for the 3rd step in each cycle of operation.

The described first step: receiving terminal is periodically measured the large scale channel fading information in the distributed MIMO mobile communication system, and this feedback information is returned transmitting terminal, obtains large-scale channel information matrix G;

G＝diag(g ₁，g ₂，…，g _NL)＝diag(L ₁I _L，L ₂I _L，…，L _NI _L)[1]；

Wherein, N is a port number, and L is the number of antennas on each port, L _iRepresent i the large scale fading coefficients on the port, and:

g _(i-1)L+1＝g _(i-1)L+2＝…＝g _iL＝L _i，i＝1，2，…，N [2]；

$L_i=d_i^{-\mathrm{\α}/2}{10}^{{\mathrm{\ξ}}_i/20}---\left[3\right];$

α is the path loss index; d _iIt is the distance of i antenna port of travelling carriage distance;

σ wherein _{DB, i}Be the shadow fading standard deviation between travelling carriage and the port i, unit is dB.

Described second step: the base station is carried out water injection power according to the large scale channel fading information that receives and is distributed between each port;

Power water filling model representation between port is:

$C_{\mathrm{up}}=\underset{Q}{\max }{\log }_2\det (I_N+\frac{N}{{\mathrm{\σ}}_n^2}{\mathrm{DQD}}^H)---\left[4\right];$

s.t.tr(Q)≤P _T

Wherein, D=diag (L ₁, L ₂..., L _N) be the port information matrix, Q=diag (Q ₁, Q ₂..., Q _N) be the power division matrix between port, P _TIt is total transmitting power;

This model separate for:

$Q_i={[u-\frac{{\mathrm{\σ}}_n^2}{{\mathrm{NL}}_i^2}]}^{+},i=\mathrm{1,2},...,N---\left[5\right];$

Wherein, parameters u by

Determine;

Formula 4 and formula 5 explanations, the port channel condition is good more, and the power of distribution is just many more; Otherwise it is few more.

Described the 3rd step: according to the power distribution result Q that each port obtains, on each port, carry out constant power and distribute, obtain final effective antenna subset and power division matrix P thereof.

p _(i-1)L+1＝p _(i-1)L+2…＝p _iL＝Q _i/L [6]

Wherein, Q _iRepresent the power distribution result that obtains on i the port, i=1,2 ..., N, power division matrix P=diag (P ₁, P ₂..., P _NL).The realization of this method does not need known whole channel information, only need known large-scale channel information, two kinds of power allocation schemes of tradition are combined, when realizing power division, realize the selection of antenna, therefore improved the performance of system effectively and reduced implementation complexity.

Beneficial effect: power division and antenna selecting method can improve the mobile communication system power efficiency in the distributed MIMO of the present invention system, improve the antenna selecting method and the changing method of many antenna mobile communication systems, ensure the mobility requirement of mobile communication system.The groundwork of algorithm is that the water injection power of calculating between port is distributed, but since during this power division based on large-scale channel information, therefore complexity is lower in the real system running.

Description of drawings

Fig. 1 is the operational process schematic diagram of transmit power allocations and antenna selecting method in the distributed MIMO system.

Fig. 2 is the system configuration schematic diagram of transmit power allocations and antenna selecting method in the distributed MIMO system.

Embodiment

Power division and antenna selecting method in the distributed MIMO of the present invention system, the large-scale channel information that the base station is measured and fed back to according to receiving terminal is determined at the transmitting power and the antenna of communication of mobile terminal.

In the distributing antenna system operational process of power division and antenna selecting method as shown in Figure 1, concrete steps are as follows:

The first step: receiving terminal is periodically measured the large scale channel fading information in the distributed MIMO mobile communication system, and this feedback information is returned transmitting terminal, obtains large-scale channel information matrix G;

G＝diag(g ₁，g ₂，…，g _NL)＝diag(L ₁I _L，L ₂I _L，…，L _NI _L)[1]

Wherein, N is a port number, and L is the number of antennas on each port, represents i the large scale fading coefficients on the port, fading coefficients,

And

g _(i-1)L+1＝g _(i-1)L+2＝…＝g _iL＝L _i，i＝1，2，…，N [2]；

$L_i=d_i^{-\mathrm{\α}/2}{10}^{{\mathrm{\ξ}}_i/20}---\left[3\right];$

α is the path loss index; d _iIt is the distance of i antenna port of travelling carriage distance;

σ wherein _{DB, i}Be the shadow fading standard deviation between travelling carriage and the port i, unit is dB.

Second step: the base station is carried out water injection power according to the large scale channel fading information that receives and is distributed between each port;

Power water filling model representation between port is:

$C_{\mathrm{up}}=\underset{Q}{\max }{\log }_2\det (I_N+\frac{N}{{\mathrm{\σ}}_n^2}{\mathrm{DQD}}^H)---\left[4\right];$

s.t.tr(Q)≤P _T

Wherein, D=diag (L ₁, L ₂..., L _N) be the port information matrix, Q=diag (Q ₁, q ₂..., Q _N) be the power division matrix between port, P _TIt is total transmitting power.

This model separate for:

$Q_i={[u-\frac{{\mathrm{\σ}}_n^2}{{\mathrm{NL}}_i^2}]}^{+},$ i＝1，2，…，N [5]；

Wherein, parameters u by

Determine.

4 and 5 explanations, the port channel condition is good more, and the power of distribution is just many more; Otherwise it is few more.When being 0, the transmitting power of distributing on certain antenna just means also that this antenna does not have selected effective antenna as system to come transmission signals.Therefore this method has also realized a day line options when utilizing large scale decline information to carry out power division.This method combines two kinds of traditional power distribution methods, carries out water injection power according to the port information matrix D and distribute between port, then carries out simple constant power and distribute on port.Have tangible grand diversity performance and have tangible micro diversity characteristic on the port between this and distributed MIMO system middle port and adapt.

The 3rd step: according to the power distribution result Q that each port obtains, on each port, carry out constant power and distribute, obtain final effective antenna subset and power division matrix P thereof.

p _(i-1)L+1＝p _(i-1)L+2…＝p _iL＝Q _i/L [6]；

Wherein, Q _iRepresent the power distribution result that obtains on i the port, i=1,2 ..., N, power division matrix P=diag (P ₁, P ₂..., P _NL).

Above content is to further describing that the present invention did in conjunction with concrete preferred implementation; can not assert that the specific embodiment of the present invention only limits to this; for the general technical staff of the technical field of the invention; without departing from the inventive concept of the premise; can also make some simple deduction or replace, all should be considered as belonging to the present invention and determine scope of patent protection by claims of being submitted to.

Claims (4)

1. power division and antenna selecting method in the distributed MIMO system that can improve the mobile communication system power efficiency is characterized in that, may further comprise the steps:

The first step: receiving terminal is periodically measured the large scale channel fading information in the distributed MIMO mobile communication system, and this large scale channel fading feedback information is returned transmitting terminal;

Second step: the base station is carried out water injection power according to the large scale channel fading information that receives and is distributed between each port;

The 3rd step:, on each port, carry out constant power and distribute according to the water injection power allocation result that each port obtains;

Each power configuration and the quick selection course of antenna are to repeat for the 3rd step in each cycle of operation.

2. power division and antenna selecting method in a kind of according to claim 1 distributed MIMO system that can improve the mobile communication system power efficiency is characterized in that:

The described first step: receiving terminal is periodically measured the large scale channel fading information in the distributed MIMO mobile communication system, and this feedback information is returned transmitting terminal, obtains large-scale channel information matrix G;

G＝diag(g ₁，g ₂，…，g _NL)＝diag(L ₁I _L，L ₂I _L，…，L _NI _L)[1]；

Wherein, N is a port number, and L is the number of antennas on each port, L _iRepresent i the large scale fading coefficients on the port, and:

g _(i-1)L+1＝g _(i-1)L+2＝…＝g _iL＝L _i，i＝1，2，…，N [2]；

$L_i=d_i^{-\mathrm{\α}/2}{10}^{{\mathrm{\ξ}}_i/20}---\left[3\right];$

α is the path loss index; d _iIt is the distance of i antenna port of travelling carriage distance;

σ wherein _{DB, i}Be the shadow fading standard deviation between travelling carriage and the port i, unit is dB.

3. power division and antenna selecting method in a kind of according to claim 1 distributed MIMO system that can improve the mobile communication system power efficiency is characterized in that:

Described second step: the base station is carried out water injection power according to the large scale channel fading information that receives and is distributed between each port;

Power water filling model representation between port is:

$C_{\mathrm{up}}=\underset{Q}{\max }{\log }_2\det (I_N+\frac{N}{{\mathrm{\σ}}_n^2}{\mathrm{DQD}}^H)---\left[4\right];$

s.t.tr(Q)≤P _T

Wherein, D=diag (L ₁, L ₂..., L _N) be the port information matrix, Q=diag (Q ₁, Q ₂..., Q _N) be the power division matrix between port, P _TIt is total transmitting power;

This model separate for:

$Q_i={[u-\frac{{\mathrm{\σ}}_n^2}{{\mathrm{NL}}_i^2}]}^{+},$ i＝1，2，…，N [5]；

Wherein, parameters u by

Determine;

Formula 4 and formula 5 explanations, the port channel condition is good more, and the power of distribution is just many more; Otherwise it is few more.

4. power division and antenna selecting method in a kind of according to claim 1 distributed MIMO system that can improve the mobile communication system power efficiency is characterized in that:

Described the 3rd step: according to the power distribution result Q that each port obtains, on each port, carry out constant power and distribute, obtain final effective antenna subset and power division matrix P thereof.

p _(i-1)L+1＝p _(i-1)L+2…＝p _iL＝Q _i/L [6]

Wherein, Q _iRepresent the power distribution result that obtains on i the port, i=1,2 ..., N, power division matrix P=diag (P ₁, P ₂..., P _NL).