CN1829131A - Resource distributing method in OFDM wireless multimedia system - Google Patents

Abstract

The present invention refers to resources allocation method for multi-user single/multiple aerial OFDM wireless multimedia system. It contains distributing transmission video carrier wave to user, the rest carrier wave used in transmitting voice to solve system bandwidth resource consume problem in all carrier wave transmitting voice, adopting time division multiplexing mode transmitting voice carrier wave for further reducing band width consume, adopting frequency hopping scheme suppressing other cell interference in voice distributed carrier wave, according to multimedia professional character, finding out carrier wave with maximum channel noise ratio in resources allocation, and distributing said carrier wave to user, then according to user's rate and miss bit rate requirement to calculate and distribute power to each user for satisfying professional requirement.

Description

Resource allocation methods in the OFDM wireless multimedia system

Technical field

Resource allocation methods when the present invention relates to utilize OFDM (OFDM) system to transmit the radio multimedium business.

Background technology

Along with the fusion gradually of wireless network, multimedia technology and internet, people are more and more higher to the requirement of the type of radio communication service and quality.For satisfying the requirement of radio multimedium and high speed data transfers, need the Development of New Generation wireless communication system.In the new generation of wireless system, to network layer, will extensively adopt some new technologies, as OFDM (OFDM), many antennas input and output (MIMO) etc. from physical layer, media access control layer.

OFDM is divided into many orthogonal sub-channels to channel at frequency domain, and whole wideband frequency selective channel is divided into the subchannel of relatively flat, simultaneously, inserts Cyclic Prefix (CP) as protection at interval at each OFDM intersymbol, has reduced intersymbol interference (IST) greatly.Because OFDM has advantages such as ability of anti-multipath is strong, generally believes that it is the key technology of new generation of wireless transmission link.

Mimo system is meant and is sending and receiving terminal use multi-antenna array that it can significantly improve power system capacity (spectrum efficiency) and wireless transmission link quality (bit error rate).The mode of utilizing the MTMO technology to improve power system capacity and transmission quality comprises two classes: space division multiplexing (SM) and space diversity (SD).The MIMO OFDM transmission technology that combines with OFDM as the MIMO that proposes towards the new generation of wireless information network also is subjected to extensive concern.The MIMO OFDM technology that MIMO combines with OFDM has both advantages, it both resolved into one group of parallel flat fading channel to frequency selectivity MTMO fading channel by the OFDM modulation, utilize MIMO to improve power system capacity again, be applicable to the multimedia service of high quality.

As everyone knows, the wireless system of practicability must be supported multi-user communication.Therefore, no matter be general ofdm system, still the ofdm system of many antennas all need have the ability of supporting that the multi-user inserts.Multi-user OFDM allows a plurality of users to share an OFDM symbol.Existing fixed channel allocation mode, all can be used for multi-user OFDM system as time division multiple access (TDMA), frequency division multiple access (FDMA), code division multiple access (CDMA) and space division multiple access (SDMA), they distribute resources such as different time slots, frequency, sign indicating number to give each user respectively.

FDMA is applied to OFDM and is called OFDM (OFDMA), and it is in each OFDM symbol, for each user distributes a part of subcarrier in all carrier waves.When unknown each user's of transmitter channel condition information (CSI), can be that each user distributes one group of subcarrier arbitrarily.And when the channel response of transmitter known users, transmitting terminal is given the user according to channel condition information self adaptation allocation of subcarriers, obtains any allocation of subcarriers more performance of each user of comparison.When OFDMA is applied to when up, all insert that users can work and are user's dynamic bandwidth allocation under low-power amplifier.When it is applied to when descending, to the parallel emission of a plurality of users data, can be by adjusting subcarrier down transmitting power control link-quality.Compare with TDMA, the OFDMA advantage is dynamic distributing carrier wave, paired pulses noise and disturb very strong robustness is arranged.At present, OFDMA is adopted by IEEE 802.16 communication standards such as grade.

During OFDMA system transmissions multimedia service, it is to be solved to exist some problems to need.The radio multimedium business mainly comprises speech and video traffic, and two class business have different service features and business need, require low bit error rate as video traffic, and voice service allows a fixed response time.In the general ofdm system,, all adopted all carrier waves of each OFDM symbol to transmit no matter to speech (audio frequency), video traffic.Yet for voice service, if utilize whole OFDM carrier waves to transmit this business, its bandwidth is far above the bandwidth demand that transmits voice service, and this has wasted system resource.In IEEE802.11a and Hiperlan/2 standard, each carrier bandwidths is 20MHz/64=312.5KHz, and this is higher than speech transmissions and requires bandwidth.Expend for reducing bandwidth resources, needing increases carrier number (IDFT counts), but has improved system complexity.Therefore, the present invention proposes a kind of method for managing resource to address this problem.

The list of references tabulation:

[1] G.J.Foschini, M.J.Gans are published in Wireless PersonalCommunications, the article that is entitled as " On limits ofwireless communications in fading environment when usingmultiple antennas " on 19986 (3) the 311st～315 pages.

[2] V.Tarokh, N.Scshadri, A.R.Calderband are published in IEEE Trans.On IT, the article that is entitled as " Space-time codes for highdata rate wireless communication:Performance critierion andcode construction " on 1,998 44 (2) the 744th～765 pages.

[3] E.Lawrey is published in the article that is entitled as " Multiuser OFDM " on the 761st～764 page of the Proc.International Symposium onSignal Processing and its Applications.

Summary of the invention

Resource allocation methods when the object of the present invention is to provide a kind of multi-user's list/multi-antenna orthogonal frequency division multiplexing system to transmit the radio multimedium business.

In the multimedia communication, the user's communications business is the multimedia service that comprises speech (audio frequency) and video.When telex network, if utilize all carrier waves of OFDM symbol to transmit voice service, then its bandwidth is far above the bandwidth demand that transmits voice service, and this has wasted system resource.Be head it off, in the scheme that the present invention proposes, distribute the carrier wave of transmission of video earlier for the user, remaining carrier wave is used for transporting speech, and this is different from and general OFDM radio multimedium transmission means.In the general system, at a time, all carrier waves of OFDM symbol all are used to transmit independent speech or video traffic.Adopt this allocation of carriers mode, system bandwidth resource cost problem in the time of can solving all carrier transmission speeches.

For further lowering consumption of broadband, the present invention adopts the Time Division Multiplexing mode in the OFDM carrier wave that transmits speech.Consider under many cell environments that for suppressing the interference of other sub-districts, to distributing to the carrier wave of speech, adopt frequency hopping (FH) scheme, its particular carrier wave frequency hopping mode can be adopted in each sub-district, with anti-presence of intercell interference.

Consider that speech and video traffic have different service features and business need, real-time as the voice service requirement, video traffic requires low bit error rate, and then proposes rational Resource Allocation Formula.At the feature of video traffic, the target of its resource allocation is under constraintss such as certain bit error rate, power, makes throughput of system the highest.Among the present invention, the method that addresses this problem is to find the carrier wave of user's peaked channal noise ratio, and gives the user this allocation of carriers; Then, according to user's speed and bit error rate requirement, calculate and distribute power to each user.

Define system has N _TotIndividual carrier wave and K user inserts, and each carrier wave can only be utilized by a user, and the carrier number of distributing for user k is N ^(k), for the user distributes N ^(k)The individual carrier wave that is used for the transmission of video business, remaining $N^{\left(k\right)}-N_{\mathrm{video}}^{\left(k\right)}=N_{\mathrm{voice}}^{\left(k\right)}$ Individual carrier wave is used for the transmission of audio business,

Wherein said video carrier allocation step is:

(1) to user k ∈ [1, K] arbitrarily, carrier wave $n\∈[1,N_{\mathrm{video}}^{\left(k\right)}],$ Do not give user k distributing carrier wave n; Defining carrier set to be allocated is $N=\left[\begin{array}{cccc}1& 2& \·\·\·& \underset{k}{\mathrm{\Σ}}{N}_{\mathrm{video}}^{\left(k\right)}\end{array}\right]$

(2) counting initialization step, user's count initialized k=1 distributes to the carrier wave count initialized i=0 of user k;

(3) calculation procedure in set N=scope, is calculated each carrier channel noise ratio, relatively and obtain the carrier wave n of high channel noise ratio;

(4) allocation step, distributing carrier wave n gives user k transmission of video business;

(5) carrier set step of updating is upgraded carrier set, promptly concentrates from total carrier wave to deduct the carrier wave N=N-{n} that has distributed;

(6) subscribers carrier set step of updating more is newly assigned to user k carrier wave counting i=i+1;

(7) determining step is if i is not more than N _Video ^(k), then change calculation procedure at next time slot to user k distributing carrier wave; Otherwise, change next step processing;

(8) user's step of updating is upgraded user number counting k=k+1;

(9) determining step if k is not more than K, then changes calculation procedure and continues to handle; Otherwise, finish.

The professional feature of speech (audio frequency) is that the transmission rate of its requirement is lower, and generally remains unchanged.For complexity that system is realized is low, to the resource allocation employing of the voice service carrier wave identical, power distribution method with video traffic.Compare with the video carrier distribution, difference is that carrier set is the sound carrier collection.Particularly, the allocation of carriers step is:

(1) to user k ∈ [1, K] arbitrarily, carrier wave $n\∈[1,N_{\mathrm{voice}}^{\left(k\right)}],$ Do not give user k distributing carrier wave n; Defining carrier set to be allocated is $N=\left[\begin{array}{cccc}1& 2& \·\·\·& \underset{k}{\mathrm{\Σ}}{N}_{\mathrm{voice}}^{\left(k\right)}\end{array}\right]$

(2) counting initialization step, user's count initialized k=1 distributes to the carrier wave count initialized i=0 of user k;

(3) calculation procedure in set N=scope, is calculated each carrier channel noise ratio, relatively and obtain the carrier wave n of high channel noise ratio;

(4) allocation step, distributing carrier wave n gives user k transmission of video business;

(5) carrier set step of updating is upgraded carrier set, promptly concentrates from total carrier wave to deduct the carrier wave N=N-{n} that has distributed;

(6) subscribers carrier set step of updating more is newly assigned to user k carrier wave counting i=i+1;

(7) determining step is if i is not more than N _Voice ^(k), then change calculation procedure at next time slot to user k distributing carrier wave; Otherwise, change next step processing;

(8) user's step of updating is upgraded user number counting k=k+1;

(9) determining step if k is not more than K, then changes calculation procedure and continues to handle; Otherwise, finish.

During power division, each user's sound, video carrier all adopted identical distribution method.Bit error rate as requested, transmission rate and the carrier wave that distributes calculate user's received signal noise ratio; According to channel guess value, calculate the power of each carrier wave of provisioned user again.Realize simply can after each user's allocation of carriers is finished, carrying out the power division step for making.

For many antennas ofdm system, consider the down link of the MIMO ofdm system of employing space division multiplexing mode of operation.After receiving terminal utilizes feedback channel that channel condition information is returned to transmitting terminal, channel matrix is carried out characteristic value (SVD) decompose and to resolve into the single output of a plurality of single inputs of parallel independent (SISO) channel to mimo channel.Like this, can be applied to the resource allocation methods of aforementioned single antenna ofdm system in many antennas ofdm system, the carrier number of carrier number to be allocated this moment when being single antenna is long-pending with number of transmit antennas, to the flow process of this algorithm with content is as described above described, repeat no more.

Summary is got up, and Resource Allocation Formula and effect thereof that the present invention proposes mainly comprise following several respects:

Distribute the carrier wave of transmission of video earlier for the user, remaining carrier wave is used for transporting speech, system bandwidth resource cost problem when having solved all carrier transmission speeches.

In the OFDM carrier wave that transmits speech, adopt the Time Division Multiplexing mode, further lowered consumption of broadband.

In distributing to the carrier wave of speech, adopt hopping scheme, can suppress the interference of other sub-districts.

At the feature of multimedia service, during resource allocation, find the carrier wave of user's peaked channal noise ratio, and give the user this allocation of carriers; Then, according to user's speed and bit error rate requirement, calculating also distributes power for each user.Like this, can satisfy professional requirement.

Description of drawings

Below, with reference to the accompanying drawings, the preferred embodiments of the present invention are described in detail, wherein:

Fig. 1 shows multi-user's single antenna ofdm system;

Fig. 2 shows the allocation of carriers example;

Fig. 3 is the schematic diagram that is used to explain many area interference;

Fig. 4 shows the frequency hopping example;

Fig. 5 shows the video traffic resource allocation flow process according to the embodiment of the invention;

Fig. 6 shows the allocation of carriers flow process according to the embodiment of the invention; And

Fig. 7 shows the multi-user multi-antenna ofdm system.

Embodiment

Below in conjunction with accompanying drawing the present invention is specified.Be noted that described embodiment only is for illustrative purposes, rather than limitation of the scope of the invention.

To its resource allocation methods be discussed respectively at single antenna OFDM and many antennas OFDM two class different systems.

Embodiment 1: the single antenna ofdm system

According to the multi-user OFDM system of support multimedia service of the present invention as shown in Figure 1.

At transmitting terminal, adopt 101 couples of a plurality of users' of encoder incoming bit stream to carry out chnnel coding with antinoise; Adopt 102 pairs of coding outputs of interleaver to carry out interleaving treatment to reduce the bit stream correlation; Adopt modulator 103 that the bit stream of interleaver output is modulated to symbols streams; Insertion pilot module 104 is finished and insert the pilot frequency sequence that is used for timing, channel estimating in being sent symbols streams; Adopt 105 pairs of stream of modulation symbols of IDFT processor to make N _cThe contrary discrete fourier transform (IDFT) of point; Symbols streams after 106 couples of IDFT of CP module handle adds Cyclic Prefix (CP); Radio frequency (RF) chain 107 is transmitted into channel to baseband signalling by antenna end 108 after carrier modulation.

At receiving terminal, RX module 111～111 ' down-converts to baseband signalling to the carrier signal that antenna 110～110 ' receives; Removing CP module 112～112 ' deletes the Cyclic Prefix of OFDM symbol; DFT module 113～113 ' is carried out N _cDian Lisanfushi conversion (DFT); Channel estimation module 114～114 ' utilizes the pilot frequency sequence that sends to estimate channel gain, and utilizes feedback channel that estimated result is fed back to the transmitting terminal carrier wave and select module; Signal after the DFT conversion is the recovering information bit stream after separating jumping 115～115 ', demodulation 116～116 ', deinterleaving 117～117 ', decoding 118～118 '.

Transmitting terminal carrier allocation module 109 is video, voice service distributing carrier wave according to each user's information such as received signal to noise ratio, wherein the carrier wave that transmits speech is carried out frequency-hopping spread spectrum, and allocation result delivered to transmitting terminal IDFT module 105, in these modules, form the OFDM symbol according to allocation of carriers information.

The system of setting up departments has N _TotIndividual carrier wave and K user inserts, and each carrier wave can only be utilized by a user.The carrier number of distributing for user k is N, and the user's communications business is the multimedia service that comprises speech and video.When telex network, if utilize all carrier waves of OFDM symbol to transmit voice service, then its bandwidth is far above the bandwidth demand that transmits voice service, and this has wasted system resource.

Be head it off, the present invention proposes a kind of scheme, it distributes N for the user earlier _VideoThe carrier wave of individual transmission of video, remaining N-N _Video=N _VoiceIndividual carrier wave is used for transporting speech, and shown in Fig. 2 (b), these are different with general OFDM radio multimedium transmission means.In general system, the carrier wave of OFDM is not divided into carrier wave that transmits video and the carrier wave that transmits speech; In a certain moment, all carrier waves of OFDM symbol all are used to transmit independent speech or video traffic, shown in Fig. 2 (a).By allocation of carriers mode proposed by the invention, the system bandwidth resource cost problem in the time of can solving all carrier transmission speeches.

Simultaneously, for further lowering consumption of broadband, the present invention adopts the Time Division Multiplexing mode in the OFDM carrier wave that transmits speech.And consider under many cell environments that for suppressing the interference of other sub-districts, as shown in Figure 3, to distributing to the carrier wave of speech, adopt frequency hopping (FH) scheme, FH can obtain interference diversity and frequency diversity effect.

These carrier waves by frequency mark in addition from low to high, are without loss of generality, are made as $f_1<f_2<\&CenterDot;\&CenterDot;\&CenterDot;f_{K_{\mathrm{voise}}-1}<f_{K_{\mathrm{voise}}}.$ The frequency hopping of unique user information can realize in the following manner: if a certain time slot transmits the carrier wave of this user profile is f ₅, the carrier wave that then next time slot transmits this user profile jumps to f ₄, the rest may be inferred.Its particular carrier wave frequency hopping mode can be adopted in each sub-district, with the opposing presence of intercell interference.A kind of frequency hopping example as shown in Figure 4, the stepped saltus step of user's carrier frequency.The figure shows and in the carrier wave of transporting speech, carry out the operation principle that TDM combines with FH.In each time slot,, represent with different pattern respectively with five users' of five carrier transmission speech; In the adjacent time slot, by the feasible carrier wave generation ladder saltus step that transmits the voiceband user business of FH mode.Like this, realized the useful combination of OFDMA, TDM and FH.

Consider that speech and video traffic have different service features and business need, real-time as the voice service requirement, and video traffic requires low bit error rate, and its resource allocation methods is discussed respectively below.Do earlier to give a definition:

There is N in system _TotIndividual carrier wave and K user inserts, and each carrier wave can only be utilized by a user, and the carrier number of distributing for user k is N ^(k), for the user distributes N ^(k)The individual carrier wave that is used for the transmission of video business, remaining $N^{\left(k\right)}-N_{\mathrm{video}}^{\left(k\right)}=N_{\mathrm{voice}}^{\left(k\right)}$ Individual carrier wave is used for the transmission of audio business,

(A) the interchannel noise ratio of n the carrier wave of user k is $H_{k,n}=\frac{h_{k,n}^2}{N_{0}B/N},$ H wherein _{K, n}Be the channel gain of n the carrier wave of user k, N ₀Be the white Gauss noise power spectral density, B is a channel width, noise power σ ²=N ₀B/N; If distributing to the power of n the carrier wave of user k is p _{K, n}, then this user's received signal noise ratio is SNR _{K, n}=p _{K, n}H _{K, n}, p _{K, n}Satisfy total power constraint $\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{p}_{k,n}\&le;P_{\mathrm{tot}},$ P _TotBe gross power;

(B) adopt square MQAM modulation, its bit error rate (BER) with the approximate function pass of user's received signal noise ratio is $\mathrm{BER}\&ap;0.2\exp \left[\frac{-1.6\mathrm{SN}{R}_{k,n}}{2^{r_{k,n}}-1}\right];$ And

(C) know that by definition (B) speed of n the carrier wave of user k is $r_{k,n}={\log }_2(1+\frac{{\mathrm{SNR}}_{k,n}}{\mathrm{\&Gamma;}}),$ Wherein Γ=-ln (5BER)/1.6; The speed of user k is $R_k=\underset{n=1}{\overset{N^{\left(k\right)}}{\mathrm{\&Sigma;}}}\frac{B}{N^{\left(k\right)}}{\mathrm{\&rho;}}_{k,n}{r}_{k,n},$ N ^(k)For distributing to the carrier number of user k, ρ _{K, n}∈ [0,1] represents that its value is 1 or 0 only, depends on whether carrier wave n is assigned to user k, if carrier wave n is assigned to user k, then ρ _{K, n}=1, otherwise ρ _{K, n}=0; The throughput of system is $R=\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{R}_k;$

At the feature of video traffic, the target of its resource allocation is under constraintss such as certain bit error rate, power, makes throughput of system, $\max \underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}\underset{n=1}{\overset{N_{\mathrm{video}}^{\left(k\right)}}{\mathrm{\&Sigma;}}}\frac{B}{N_{\mathrm{video}}^{\left(k\right)}}{\mathrm{\&rho;}}_{k,n}{\log }_2(1+\frac{{\mathrm{SNR}}_{k,n}}{\mathrm{\&Gamma;}})$ The highest, satisfy following constraints simultaneously: $1)\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}\underset{n=1}{\overset{N_{\mathrm{video}}^{\left(k\right)}}{\mathrm{\&Sigma;}}}{p}_{k,n}\&le;P_{\mathrm{tot}}^{\left(\mathrm{video}\right)};$ 2)ρ _k，n∈[0，1]；3)BER≤BER _req。

Wherein, N _k ^(video)For distributing to the carrier number of user k video traffic, P _Tot ^(video)Be the gross power of video carrier, BER _ReqFor requiring bit error rate.

A kind of method that addresses this problem is to find the carrier wave of user's peaked channal noise ratio, and gives the user this allocation of carriers; Simultaneously, according to user's speed and bit error rate requirement, utilize the formula among definition (B), (C) to calculate the power of distributing to each user, as Fig. 5.Wherein, the allocation of carriers algorithm as shown in Figure 6, step is as follows:

S601, to user k ∈ [1, K] arbitrarily, carrier wave $n\&Element;[1,N_{\mathrm{video}}^{\left(k\right)}],$ Do not give user k distributing carrier wave n; Defining carrier set to be allocated is $N=\left[\begin{array}{cccc}1& 2& \&CenterDot;\&CenterDot;\&CenterDot;& \underset{k}{\mathrm{\&Sigma;}}{N}_{\mathrm{video}}^{\left(k\right)}\end{array}\right]$

S602, the counting initialization step, user's count initialized k=1 distributes to the carrier wave count initialized i=0 of user k;

S603, calculation procedure in set N=scope, is calculated each carrier channel noise ratio, relatively and obtain the carrier wave n of high channel noise ratio;

S604, allocation step, distributing carrier wave n gives user k transmission of video business;

S605, the carrier set step of updating is upgraded carrier set, promptly concentrates from total carrier wave to deduct the carrier wave N=N-{n} that has distributed;

S606, user k carrier set step of updating more is newly assigned to user k carrier wave counting i=i+1;

S607, determining step is if i is not more than N _Video ^(k), then forward calculation procedure to, at next time slot to user k distributing carrier wave; Otherwise, forward next step processing to;

S608, user's step of updating is upgraded user number counting k=k+1;

S609, determining step if k is not more than K, then forwards calculation procedure to and continues to handle; Otherwise, finish.

The professional feature of speech (audio frequency) is that the transmission rate of its requirement is lower, and generally remains unchanged.Comparatively speaking, the requirement of its resource allocation, low than video traffic, for complexity that system is realized is low, among the present invention, the distribution method identical with video traffic to the resource allocation employing of voice service, compare with the video carrier distribution, difference is that carrier set is the sound carrier collection.The power division step of voice service is identical with video traffic, no longer repeats.

After each user's carrier wave is distributed in acquisition, need carry out power division to each carrier wave.During power division, at first, bit error rate as requested and transmission rate are by formula $\mathrm{BER}\&ap;0.2\exp \left[\frac{-1.6{\mathrm{SNR}}_{k,n}}{2^{r_{k,n}}-1}\right]$ The received signal noise ratio that calculates the user is SNR _{K, n}Then, according to channel guess value and formula S NR _{K, n}=p _{K, n}H _{K, n}, calculate the power of each carrier wave of distributing to user k.

Embodiment 2: many antennas OFDM

Consider the down link (broadcast channel) of the MIMO ofdm system of employing space division multiplexing mode of operation, transmitting terminal (base station BS) is installed N _TWidth of cloth antenna is installed N at each user's receiving terminal _RWidth of cloth antenna.

According to the embodiment of MTMO ofdm system of the present invention as shown in Figure 7.

At transmitting terminal, input bit is flowed through and is multiplexed into every transmit antennas end after the serial/parallel conversion 701; To the bit stream of every antenna branch end, adopt encoder 702～702 ' that incoming bit stream is carried out chnnel coding with antinoise; Adopt interleaver 703～703 ' that coding is exported and carry out interleaving treatment to reduce the bit stream correlation; Adopt modulator 704～704 ' that the bit stream of interleaver output is modulated to symbols streams; Insertion pilot module 705～705 ' is finished and insert the pilot frequency sequence that is used for timing, channel estimating in being sent symbols streams; Adopt IDFT processor 706～706 ' that stream of modulation symbols is made N _cThe contrary discrete fourier transform of point; Symbols streams after CP module 707～707 ' is handled IDFT adds Cyclic Prefix; After the antenna transmission Signal Pretreatment, rf chain 709～709 ' is transmitted into channel to baseband signalling by antenna 710～710 ' to pre-filtering (emission filtering) device after carrier modulation more than 708 pairs.

At receiving terminal, RX module 713～713 ', 720～720 ' down-converts to baseband signalling to the carrier signal that receives from antenna end 712～712 ', 720～720 '; Synchronization module 714,722 is finished frame synchronization, tracking; The function of receiving filter 715,723 is corresponding with prefilter, the compensation received signal; Removing CP module 716～716 ', 724～724 ' deletes the Cyclic Prefix of OFDM symbol; DFT module 717～717 ', 725～725 ' is carried out N _cThe Dian Lisanfushi conversion; The pilot frequency sequence that channel estimating 718,726 module utilizations send estimates channel gain, and utilizes feedback channel that estimated result is fed back to the transmitting terminal carrier wave and select module; Signal after the DFT conversion is the recovering information bit stream after separating jumping, demodulation, deinterleaving, decoding 719,727.

Transmitting terminal carrier allocation module 711 is video, voice service distributing carrier wave according to each user's information such as received signal to noise ratio, wherein the carrier wave that transmits speech is carried out frequency-hopping spread spectrum, and allocation result delivered to transmitting terminal IDFT module 706～706 ', in these modules, form the OFDM symbol according to allocation of carriers information.

The main advantage of the mimo system of space division multiplexing mode of operation is to obtain high channel capacity (spectrum efficiency).To the space division multiplexing multiaerial system, being x if transmit, is x=Vx after the pre-filtering, and the signal after the channel H transmission is y=H x+ w=HVx+ w, back signal vector y and y=U accept filter ^HY=U ^H(HVx+ w), wherein U is for launching pre-filtering battle array and V for accepting filter battle array, subscript " T " expression transposition, the Hermite transposition of subscript " H " representing matrix, channel matrix

Element h wherein _IjBe the channel fading coefficient of transmitting antenna i to reception antenna j.After receiving terminal utilizes feedback channel that channel condition information is returned to transmitting terminal, channel matrix is carried out characteristic value (SVD) decompose, obtain H=U Λ V ^H, unitary matrix U, V satisfy UU ^H=I, VV ^H=I; Diagonal matrix Λ=diag (λ ₁λ ₂λ _k), λ ₁＞λ ₂＞...＞λ _kBe the characteristic value of H, so the output y=U that accepts filter ^H(U Λ V ^H) (Vx)+U ^HW=Λ x+w, w is a noise in the formula.As seen,, can resolve into the single output of a plurality of single inputs of parallel independent (SISO) channel to mimo channel, decompose the number that the parallel sub-channels number that obtains equals nonzero eigenvalue among the H by characteristic value decomposition.Like this, can be applied to the resource allocation methods of aforementioned single antenna ofdm system in many antennas ofdm system, embodiment 1 is seen in the flow process and the description of this algorithm, repeat no more here.

Although illustrated and described the present invention at exemplary embodiments, will be understood by those skilled in the art that, under the situation that does not break away from the spirit and scope of the present invention, can carry out various other change, replacement and interpolations.Therefore, the present invention should not be understood that to be limited to above-mentioned particular instance, and should be limited by claims.

Claims (10)

1, the resource allocation methods in a kind of multi-user orthogonal frequency division multiplexing wireless multimedia system comprises:

The video carrier allocation step among a plurality of users each, in particular moment, will have the allocation of carriers peaked channal noise ratio, that be used for the transmission of video business to a described user successively and give described user;

The sound carrier allocation step, the allocation of carriers that will be used for the transmission of audio business is given each user; And

The power division step, according to each user's speed, sound, the video carrier number that bit error rate required and distributed to each user, calculating will be distributed to each user's power, and gives each user with the power division that is calculated.

2, resource allocation methods according to claim 1 is characterized in that at the carrier wave that is used for the transmission of audio business, adopts time division multiplexing mode.

3, resource allocation methods according to claim 1 and 2 is characterized in that in sound carrier, adopts the anti-many area interference of hopping scheme.

4, resource allocation methods according to claim 1 and 2, it is characterized in that in described sound carrier allocation step, at among a plurality of users each, in particular moment, will have the allocation of carriers peaked channal noise ratio, that be used for the transmission of audio business to a described user successively and give described user;

5, resource allocation methods according to claim 1 and 2 is characterized in that comprising the step that defines following parameter:

There is N in system _TotIndividual carrier wave and K user inserts, and each carrier wave can only be utilized by a user, and the carrier number of distributing for user k is N ^(k), for the user distributes N _Video ^(k)The individual carrier wave that is used for the transmission of video business, remaining $N^{\left(k\right)}-N_{\mathrm{video}}^{\left(k\right)}=N_{\mathrm{voice}}^{\left(k\right)}$ Individual carrier wave is used for the transmission of audio business,

(A) the interchannel noise ratio of n the carrier wave of user k is $H_{k,n}=\frac{h_{k,n}^2}{N_{0}B/N},$ H wherein _{K, n}Be the channel gain of n the carrier wave of user k, N ₀Be the white Gauss noise power spectral density, B is a channel width, noise power σ ²=N ₀B/N; If distributing to the power of n the carrier wave of user k is p _{K, n}, then this user's received signal noise ratio is SNR _{K, n}=p _{K, n}H _{K, n}, p _{K, n}Satisfy total power constraint $\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{p}_{k,n}\&le;P_{\mathrm{tot}},$ P _TotBe gross power;

(B) adopt square MQAM modulation, its bit error rate (BER) with the approximate function pass of user's received signal noise ratio is $\mathrm{BER}\&ap;0.2\exp \left[\frac{-1.6{\mathrm{SNR}}_{k,n}}{2^{r_{k,n}}-1}\right];$ And

(C) know that by definition (B) speed of n the carrier wave of user k is $r_{k,n}={\log }_2(1+\frac{{\mathrm{SNR}}_{k,n}}{\mathrm{\&Gamma;}}),$ Wherein Г=-ln (5BER)/1.6; The speed of user k is $R_k=\underset{n=1}{\overset{N^{\left(k\right)}}{\mathrm{\&Sigma;}}}\frac{B}{N^{\left(k\right)}}{\mathrm{\&rho;}}_{k,n}{r}_{k,n},$ N ^(k)For distributing to the carrier number of user k, ρ _{K, n}∈ [0,1] represents that its value is 1 or 0 only, depends on whether carrier wave n is assigned to user k, if carrier wave n is assigned to user k, then ρ _{K, n}=1, otherwise ρ _{K, n}=0; The throughput of system is $R=\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{R}_k;$

Wherein said video carrier allocation step comprises:

Initialization step, to user k ∈ [1, K] arbitrarily, carrier wave $n\&Element;[1,N_{\mathrm{video}}^{\left(k\right)}],$ Do not give user k distributing carrier wave n; Defining carrier set to be allocated is $N=\left[\begin{array}{cccc}1& 2& \&CenterDot;\&CenterDot;\&CenterDot;& \underset{k}{\mathrm{\&Sigma;}}{N}_{\mathrm{video}}^{\left(k\right)}\end{array}\right];$

The counting initialization step, user's count initialized k=1 distributes to the carrier wave count initialized i=0 of user k;

Calculation procedure in set N=scope, is calculated each carrier channel noise ratio, relatively and obtain the carrier wave n of high channel noise ratio;

Allocation step, distributing carrier wave n gives user k transmission of video business;

The carrier set step of updating is upgraded carrier set, promptly concentrates from total carrier wave to deduct the carrier wave N=N-{n} that has distributed;

Subscribers carrier set step of updating, the carrier wave that more is newly assigned to user k is counted i=i+1;

Determining step is if i is not more than N _Video ^(k), then forward to calculation procedure at next time slot to user k distributing carrier wave; Otherwise, forward next step processing to;

User's step of updating is upgraded user number counting k=k+1;

Determining step if k is not more than K, then changes calculation procedure and continues to handle; Otherwise, finish.

6, resource allocation methods according to claim 5 is characterized in that described power division step comprises:

Bit error rate as requested and transmission rate are by formula $\mathrm{BER}\&ap;0.2\exp \left[\frac{-1.6{\mathrm{SNR}}_{k,n}}{2^{r_{k,n}}-1}\right]$ The received signal noise ratio that calculates the user is SNR _{K, n}And

According to channel guess value and formula S NR _{K, n}=p _{K, n}H _{K, n}, dispensed is given the power of each carrier wave of user k.

7, resource allocation methods according to claim 5 is characterized in that described sound carrier allocation step comprises:

Defining carrier set to be allocated is $N=\left[\begin{array}{cccc}1& 2& \&CenterDot;\&CenterDot;\&CenterDot;& \underset{k}{\mathrm{\&Sigma;}}{N}_{\mathrm{voice}}^{\left(k\right)}\end{array}\right],$

In set N=scope, calculate each carrier channel noise ratio, relatively and obtain the carrier wave n of high channel noise ratio;

Distributing carrier wave n is used for the transmission of audio business for user k;

Upgrade carrier set, concentrate from total carrier wave to deduct the carrier wave N=N-{n} that has distributed, and the carrier wave counting i of distributing user k is added 1;

Judge whether i is not more than N _Voice ^(k)If, then forward calculation procedure to, at next time slot to user k distributing carrier wave; Otherwise, forward next step processing to;

Carry out at next user

Judge, if last user that described next user is not a distributing carrier wave then forwards the step of calculating each carrier channel noise ratio to and continues iterative processing; Otherwise described sound carrier distributes end.

8,, it is characterized in that described multi-user orthogonal frequency division multiplexing system is multi-user's single antenna ofdm system according to any one the described resource allocation methods in the claim 1 to 7.

9,, it is characterized in that described multi-user orthogonal frequency division multiplexing system is a multi-user and multi-antenna OFDM system according to any one the described resource allocation methods in the claim 1 to 7.

10, a kind of resource allocation methods of multi-user and multi-antenna OFDM wireless multimedia system comprises step:

Transmitting terminal emission pilot frequency sequence, receiving terminal is estimated the channel gain matrix coefficient, and utilizes feedback channel that this information is returned to transmitting terminal;

Transmitting terminal carries out characteristic value decomposition to channel matrix, thereby multi-antenna channel is decomposed into the single delivery channel of a plurality of single inputs of parallel independent; And

At the single delivery channel of described a plurality of single inputs, use according to any one the described resource allocation methods in the claim 1 to 7.

Images