CN106376090A - User scheduling and power control collaboration method for LTE-A heterogeneous network - Google Patents

Abstract

The invention discloses a user scheduling and power control collaboration method for an LTE-A heterogeneous network. The method comprises the following steps: step 1, collecting channel state information; step 2, initializing iterative parameters; step 3, calculating optimal transmitting power of each user; step 4, selecting resource blocks and scheduling users; step 5, updating the iterative parameters; step 6, judging whether a stop condition is satisfied, and if not, returning to step 3; and step 7, outputting a result. By adoption of the method provided by the invention, the minimum number of the resource blocks RB for interference collaboration at low transmitting power can be realized, the method has the advantages of being fast and efficient, and can well meet the requirements of the 4G LTE-A mobile communication network for reducing the cross layer interference.

Description

User scheduling for lte-a heterogeneous network and Power Control Synergistic method

Technical field

The invention belongs to radio communication and signal of communication processing technology field, especially for the use of lte-a heterogeneous network Family scheduling and Power Control Synergistic method.

Background technology

Require for adapting to higher cell capacity, heterogeneous network framework be considered as 4g Long Term Evolution advanced (lte-a, Long term evolution-advanced) the important network model of one of system.In one typical heterogeneous network Include different types of base station, extra portion in the coverage of traditional macro base station (macro base station, mbs) Affix one's name to multiple low power base station, such as femto base station (pico base station, pbs), Home eNodeB (femto bs), relaying base Stand.In the heterogeneous network model being made up of mbs and pbs, due to huge transmit power gap between mbs and pbs, one Under a little communication scenes, such as some mobile subscribers (mobile station, ms) outside pbs cell edge, although with respect to mbs, Ms is apart from pbs closer to ms still can tend to same mbs and be communicated.This makes ms can consume bigger uplink transmission power, with When pbs can be caused serious cross-layer disturb.

Content of the invention

Goal of the invention: for the deficiencies in the prior art, propose one kind in the present invention for isomery Cellular Networks in 4g lte-a The user scheduling of network and the Synergistic method of Power Control, realize being used for the Resource Block of interference synergic under low transmit power The minimum of (resource block, rb) number.

The present invention towards 4g lte-a wireless communication networks to reduce cross-layer interference requirement it is proposed that a kind of Power Control with User scheduling Synergistic method is minimizing used Resource Block.

Technical scheme: for achieving the above object, the invention discloses for lte-a heterogeneous network user scheduling with Power Control Synergistic method, comprises the steps:

Step 1 is it is assumed that comprise mbs and p femto base station pbs of 1 macro base station, femto base station pbs in cordless communication network It is randomly dispersed in the coverage of macro base station mbs, orderWithRepresent macrocell mobile subscriber mms respectively The picocell comprising in the set of (macro mobile station, macrocell mobile subscriber), l-th femto base station pbs The set of mobile subscriber pms (pico mobile station, picocell mobile subscriber) with picocell all be in little The set of the mobile subscriber in area's spreading range, the gesture of corresponding set is expressed as follows:

Each picocell contains an er-pms, and system overall bandwidth b of macrocell is divided into n Resource Block rb, With setRepresent；

Collection channel condition information between macro base station mbs and k-th mms on n-th Resource BlockAnd l-th Femto base station pbs and be in the channel condition information between mobile subscriber in the range of cell extensionL value is 1～p, on Mark m represents macro base station, subscript p_lRepresent l-th femto base station, n value is 1～n；

Step 2, initialization scheduling instruction vectorInformation rate r that er-pms j obtains_j,ach =0

Step 3, calculates the transmit power that mms user k can use on n-th Resource Block, and chooses n-th Resource Block On optimum mms user

Step 4, finds the mobile subscriber j being in the range of cell extension meeting condition^*, to meeting, being in of condition is little Mobile subscriber j in area's spreading range^*, find best resource blocks n^*；

Step 5, updates scheduling indicatorWherein r_j,achRepresent The information rate obtaining,Represent best resource blocks n^*Distribute to retrievable information rate during er-pms j；

Step 6, judges whether to meet stop conditionIf meeting stop condition, stopping and exporting's Value；If being unsatisfactory for, return to step 3.

In step 3 of the present invention, transmit power mms user k is calculated by equation below and can use on n-th Resource Block Transmit power p_k,n:

$\begin{array}{cc}{p}_{k,n}=\frac{{\mathrm{\σ}}_{l=1}^p{p}_p|h_{k,n}^{p_l}{|}^2+n_0\frac{b}{n}}{|h_{k,n}^m{|}^2}\·{\mathrm{\γ}}_{k,req}& \∀k,n\end{array},$

Wherein γ_k,reqRepresent that the Signal to Interference plus Noise Ratio of k-th mms requires, n₀Represent noise power spectral density, p_p Represent p-th femto base station.

The mms user of the optimum on n-th Resource Block in step 3 of the present invention, is chosen by equation below

In step 4 of the present invention, find the mobile subscriber j being in the range of cell extension meeting following condition^*:

Wherein, r_j,reqRepresent the rate requirement being in the er-pms j in the range of cell extension, r_j,achRepresent er-pms family The information rate of j acquisition.

In step 4 of the present invention, for the mobile subscriber j meeting in the range of the cell extension of condition^*, find and meet public affairs as follows Best resource blocks n of formula^*:WhereinRepresent mobile subscriber j^*Make Use Resource Block n^*When retrievable information rate.

The present invention is calculated by following formula

$r_{j^{*},n}=\frac{b}{n}{\log }_2\left(1+\frac{p_p|h_{j^{*},n}^{p_l}{|}^2}{p_{m,n}|h_{j^{*},n}^m{|}^2+{\mathrm{\σ}}_{l^{\′}=1,l^{\′}\&notequal;l}^p{p}_p|h_{j^{*},n}^{p_{l^{\′}}}{|}^2+n_0\frac{b}{n}}\right)$

WhereinRepresent on Resource Block n l-th femto base station pbs and be in mobile subscriber j in the range of cell extension^* Between channel condition information, p_m,nRepresent the transmit power that macro base station mbs distributes on Resource Block n,Represent in resource Macro base station mbs and mobile subscriber j on block n^*Between channel condition information,Represent the individual slight base of l ' on Resource Block n Stand pbs and mobile subscriber j^*Between channel condition information.

For solving problem of the prior art, the present invention utilizes cell range expansion technique to pass through the suitable transmission increasing pbs The cell coverage area of power expansion pbs, thus allow the ms near pbs to select (to be in cell to expand with pbs communication rather than mbs Ms in the range of exhibition is referred to as er-pms), so can effectively reduce cross-layer interference and realize load balancing simultaneously.Use in the present invention Technical scheme comprise two parts content, be optimum transmission power control technology respectively and low complex degree user scheduling algorithm.

(1) optimum transmission power control technology

For each Resource Block, select a mms and corresponding transmit power to need to consider that minimizing cross-layer does simultaneously The qos disturbing and meeting mms itself requires.It is assumed that on Resource Block n, arbitrary mms user k has a minimum sinr to want as qos Ask, then transmit power p_m,nNeed to meet below equation:

Wherein γ_k,reqRepresent that the sinr of k-th mms requires.When mbs mitigates cross-layer interference by reducing transmit power When, above formula has to meet, and therefore when Resource Block n is scheduled to mms k, the minimum transmit power of mbs distribution is

$\begin{array}{cc}{p}_{k,n}=\frac{{\mathrm{\σ}}_{l=1}^p{p}_p|h_{k,n}^{p_l}{|}^2+n_0\frac{b}{n}}{|h_{k,n}^m{|}^2}\·{\mathrm{\γ}}_{k,req}& \∀k,n\end{array},$

For arbitrary Resource Block n, give all mms and required transmit power, selection meets qos requirement to be had simultaneously The user of minimum transmit power is as optimum mmsSo can farthest reduce and from mbs, er-pms be done Disturb.Obviously there is more preferable channel condition and the mms of less qos requirement is more likely selected.The selection of so optimum mms can It is expressed as following simple optimizing problem

(2) low complex degree user scheduling algorithm

When in mbs is to macrocell, the transmit power of mms user gives, it is to the er-pms in the picocell of pbs place Interference determine after, by the selection of Resource Block, pbs can be scheduling to er-pms therein, select suitable er-pms It is allocated requiring to ensure corresponding qos with Resource Block, be always desirable to by resource block assignments as few as possible simultaneously To complete above target, the Resource Block minimization problem that therefore Resource Block select permeability can be expressed as follows:

WhereinRepresent scheduling instruction vector.r_j,reqRepresent er-pms j's Rate requirement.

Technological merit: propose the user scheduling of isomery cellular network and power control in a kind of lte-a for 4g in the present invention The synergetic of system, realization meets user qos and requires the lower number of resource blocks purpose being used for interference synergic to minimize.By testing table Bright, the method proposing in the present invention can obtain excellent performance.

Brief description

With reference to the accompanying drawings and detailed description the present invention is done and further illustrate, the present invention's is above-mentioned And/or otherwise advantage will become apparent.

Fig. 1 is the schematic diagram of a scenario of the present invention.

Fig. 2 is flow chart of the present invention.

Specific embodiment

Embodiment 1

The downlink communication scene of the 4g lte-a Wireless Heterogeneous Networks that the present embodiment considers, as shown in figure 1, include 1 Mbs and p pbs, pbs are randomly dispersed in the coverage of mbs.OrderWithRepresent mms (macro respectively Mobile station, macrocell mobile subscriber) set, institute in the set of pms comprising in l-th pbs and picocell There is the set of er-pms.The gesture of corresponding set is expressed as follows: WithFor the sake of simple, only examine Consider a mbs, each picocell contains an er-pms simultaneously.System overall bandwidth b is divided into n Resource Block rb and (uses SetRepresent).These rb distribute to corresponding ms by mbs and pbs.Noise power spectral density is n₀, simultaneously between ms and bs Average channel gain on certain rb can be obtained by information feedback, and channel gain comprises path loss, shade Decline and the impact of rapid fading.

In the case of not working in coordination with Power Control, the signal that i-th mms receives on n-th rb is added with interference makes an uproar Acoustic ratio (sinr) is represented by:

${\mathrm{sinr}}_{i,n}^m=\frac{p_m|h_{i,n}^m{|}^2}{{\mathrm{\σ}}_{l=1}^p{p}_p|h_{i,n}^{p_l}{|}^2+n_0\frac{b}{n}},$

Based on sinr, the retrievable information rate of i-th mms in mbs is represented by:

$r_i^m=\underset{n=1}{\overset{n}{\σ}}{\mathrm{\α}}_{i,n}^m\frac{b}{n}{\log }_2(1+{\mathrm{sinr}}_{i,n}^m),$

WhereinIt is scheduling indicated number, represent whether Resource Block n is scheduled to i-th ms in mbs and uses. For j-th pms in l-th pbs, its retrievable information rate can be expressed as follows by similar formula:

$r_j^{p_l}=\underset{n=1}{\overset{n}{\σ}}{\mathrm{\α}}_{j,n}^{p_l}\frac{b}{n}{\log }_2(1+{\mathrm{sinr}}_{j,n}^{p_l}),$

As shown in Fig. 2 the present invention comprises the following steps:

Step (1): collection channel condition information between mbs and k-th mms on n-th Resource BlockL-th Channel condition information between pbs and er-pms

Step (2): initiation parameter

Step (3): mbs is according to sending out that below equation to calculate that transmit power mms user k can use on Resource Block n Send power

$\begin{array}{cc}{p}_{k,n}=\frac{{\mathrm{\σ}}_{l=1}^p{p}_p|h_{k,n}^{p_l}{|}^2+n_0\frac{b}{n}}{|h_{k,n}^m{|}^2}\·{\mathrm{\γ}}_{k,req}& \∀k,n\end{array},$

And the mms user of the optimum on n-th Resource Block is chosen according to below equation

Step (4): find the er-pms j meeting following condition^*:

And to er-pms j^*, find the best resource blocks rb n meeting following formula^*

Wherein, calculated by following formula

$r_{j^{*},n}=\frac{b}{n}{\log }_2\left(1+\frac{p_p|h_{j^{*},n}^{p_l}{|}^2}{p_{m,n}|h_{j^{*},n}^m{|}^2+{\mathrm{\σ}}_{l^{\′}=1,l^{\′}\&notequal;l}^p{p}_p|h_{j^{*},n}^{p_{l^{\′}}}{|}^2+n_0\frac{b}{n}}\right),$

Step (5): update

Step (6): judge whether to meet stop conditionIf meeting stop condition, stopping and exporting's Value.If being unsatisfactory for, return to step (3).

Step (7): output result.

Embodiment 2

The performance of the power control algorithm for proposing in the checking present invention, employs lte downlink system level emulator. Following heterogeneous network topological structure, the mbs of 13 sector and 2 to 4 pbs are employed, these pbs are evenly distributed in emulation In each sector of mbs, each pbs is equipped with omnidirectional antenna.Consider two kinds of range expansion biasings of 4db and 8db.Mbs with Pbs can access whole system bandwidths.Minimum sinr required by mms is 5db, and the targeted rate of er-pms is 0.5mbps.Its He is shown in Table 1 at the setting of specific simulation parameter.

Table 1 system emulation parameter

Shown in table 2 is user scheduling proposed by the present invention and Power Control Synergistic method and resource when not adopting collaborative Block is compared using number.The Resource Block comparing under different picocell numbers and the biasing of different range expansion takies Situation,

The resource block number of table 2 averagely use

Be can be seen that by Tables 1 and 2, the inventive method can largely reduce the occupancy to Resource Block, with respect to Do not use collaborative situation, the Resource Block that the inventive method can reduce 30% about uses.

Although the present invention is illustrated with regard to preferred implementation and has been described, it is understood by those skilled in the art that Without departing from scope defined by the claims of the present invention, variations and modifications can be carried out to the present invention.

Claims (6)

1. be used for lte-a heterogeneous network user scheduling with Power Control Synergistic method it is characterised in that comprising the steps of

, it is assumed that comprising mbs and p femto base station pbs of 1 macro base station in cordless communication network, femto base station pbs is random for step 1 It is distributed in the coverage of macro base station mbs, orderWithRepresent respectively macrocell mobile subscriber mms set, the The set of picocell mobile subscriber pms comprising in l femto base station pbs is all with picocell to be in cell extension model The set of the mobile subscriber in enclosing, the gesture of corresponding set is expressed as follows:

Each picocell contains an er-pms, and system overall bandwidth b of macrocell is divided into n Resource Block rb, with collection CloseRepresent；

Collection channel condition information between macro base station mbs and k-th mms on n-th Resource BlockAnd l-th slight Base station pbs and be in the channel condition information between mobile subscriber in the range of cell extensionL value is 1～p, subscript m Represent macro base station, subscript p_lRepresent l-th femto base station, n value is 1～n；

Step 2, initialization scheduling instruction vectorThe information rate that er-pms j obtains

Step 3, calculates the transmit power that mms user k can use on n-th Resource Block, and chooses on n-th Resource Block Optimum mms user

Step 4, finds the mobile subscriber j being in the range of cell extension meeting condition^*, the cell that is in meeting condition is expanded Mobile subscriber j in the range of exhibition^*, find best resource blocks n^*；

Step 5, updates scheduling indicatorWherein r_j,achRepresent acquisition Information rate,Represent best resource blocks n^*Distribute to retrievable information rate during er-pms j；

Step 6, judges whether to meet stop conditionIf meeting stop condition, stopping and exportingValue；If no Meet, return to step 3.

2. method according to claim 1 is it is characterised in that in step 3, calculate transmit power mms by equation below Transmit power p that user k can use on n-th Resource Block_k,n:

$\begin{array}{cc}{p}_{k,n}=\frac{{\mathrm{\σ}}_{l=1}^p{p}_p|h_{k,n}^{p_l}{|}^2+n_0\frac{b}{n}}{|h_{k,n}^m{|}^2}\·{\mathrm{\γ}}_{k,req}& \∀k,n\end{array},$

Wherein γ_k,reqRepresent that the Signal to Interference plus Noise Ratio of k-th mms requires, n₀Represent noise power spectral density, p_pRepresent P-th femto base station.

3. method according to claim 1 is it is characterised in that in step 3, choose n-th Resource Block by equation below On optimum mms user

4. method according to claim 1 is it is characterised in that in step 4, the cell that is in that searching meets following condition expands Mobile subscriber j in the range of exhibition^*:

Wherein, r_j,reqRepresent the rate requirement being in the er-pms j in the range of cell extension, r_j,achRepresent that er-pmsj obtains Information rate.

5. method according to claim 4 is it is characterised in that in step 4, for the shifting meeting in the range of the cell extension of condition Employ family j^*, find best resource blocks n meeting equation below^*: WhereinRepresent mobile subscriber j^*Using Resource Block n^*When retrievable information rate.

6. method according to claim 5 is it is characterised in that calculated by following formula

$r_{j^{*},n}=\frac{b}{n}{\log }_2\left(1+\frac{p_p|h_{j^{*},n}^{p_l}{|}^2}{p_{m,n}|h_{j^{*},n}^m{|}^2+{\σ}_{l^{\′}=1,l^{\′}\&notequal;l}^p{p}_p|h_{j^{*},n}^{p_{l^{\′}}}{|}^2+n_0\frac{b}{n}}\right)$

WhereinRepresent on Resource Block n l-th femto base station pbs and be in mobile subscriber j in the range of cell extension^*Between Channel condition information, p_m,nRepresent the transmit power that macro base station mbs distributes on Resource Block n,Represent grand on Resource Block n Base station mbs and mobile subscriber j^*Between channel condition information,Represent on Resource Block n l ' individual femto base station pbs with Mobile subscriber j^*Between channel condition information.