CN101171760A - An adaptive MAC protocol based on multi-user detection - Google Patents

Abstract

A system and method is provided for a station, mobile station or otherwise, in a MC- CDMA based WLAN, CDMA based, or other multichannel wireless system, to dynamically decide to transmit in parallel with current transmissions or to select another frequency channel in the communication system. An exemplary device is well suited for wireless systems based on CDMA using a MUD. The system and method provide a means for estimating the interference of signals on the same frequency channel as determined by the MUD. Individual stations in the system can decide, in a distributed manner, if they should divert their communication link to another frequency channel, or to continue on the same frequency channel in parallel to the current communication links.

Description

A kind of adaptive MAC protocol based on Multiuser Detection

Background technology

MC-CDMA (MC-CDMA) receives much attention recently and has become the promising candidate technologies of following high capacity wireless communication network.Generally speaking, multi-transceiver technology can be resisted multipath fading; High spectrum utilization and antijamming capability are provided.MC-CDMA also has some other advantage, for example frequency spectrum diversity and opposing frequency selective fading and impulse noise.

With reference to Fig. 1, each symbol 1,2,3,4 of a user's MC-CDMA data flow multiply by each element of same spreading code, then each symbol is placed on respectively on narrow- band sub-carriers 6a, 6b, 6c, the 6d.A plurality of chips 8 are not continuous, but go up parallel transmission at different subcarrier (for example 6a).In MC-CDMA, an independent data symbol is carried out frequency domain expansion.It is such system of 4 that Fig. 1 has provided a spreading factor.Fig. 1 is that spreading factor SF is the example of 4 MC-CDMA.

Referring now to Fig. 2, a radio station 20 of preparing transmission needs to select a code channel (CCh1, CCh2, CCh3, CCh4).Having two kinds of methods to can be used for code channel selects.First method is to select a code channel before each packet of transmission.When initial, select code channel at random.In transmission afterwards, the code channel (according to standard, the radio station of being looked after is provided with a network allocation vector (NAV) for the code channel that has taken) that this radio station no longer selects other radio station to subscribe.Select the method for code channel to comprise for two steps for second kind: at first to select the code channel of traffic carrying capacity minimum, in whole connection procedure, take this code channel then.

Fig. 2 is an example of RTS/CTS access mechanism.Before inserting media, whether media at first should be detected at DIFS (distributed inter-frame space) in the radio station in the duration idle.In case it is idle that this radio station detects media, then this radio station just begins by sending RTS packet 22 notice expectation transfer of data, as shown in the figure.

All receive the RTS controlling packet and are not expectation recipient's radio station (for example: radio station 3 and radio station 4), their NAV timer 24, rollback (backoff) down counter that interrupts them and delay media are set insert, to avoid interference transfer of data.If (for example: be idle radio station 2), promptly can receive data, after one was called 28 times of short interFrameGap (SIFS), this receiver responded a CTS packet 26 to the receiver of RTS 22 so.If the receiver of RTS is in busy condition, repeat the RTS transmission after the time at a new rollback so.The mobile station that receives CTS also is provided with their NAV timer.After SIFS 30, transmitter 20 can transmit its packet 32.Finish SIFS after 36 times at Frame 32, receiver (for example the radio station 2) receives successfully by ACK 34 notices.For each transfer of data, each code channel is all followed above-mentioned standard profile formula coordination function program 38.

Fig. 3 shows an example of Multiuser Detection MUD receiver.With most of asynchronous CDMA system similarities, multi-carrier CDMA system needs a so-called multi-user detector (MUD) 40.Its reason is: in asynchronous multiple access cdma system, received signal comprises the data of all active users.The sequential mismatch can be destroyed the orthogonality between the spreading code of different user and cause multiple access to disturb (MAI).Because this reason, (for example: STA2) side need be used MUD 40 the recipient.The example of such MUD is based on the linear detector of least mean-square error (MMSE) criterion.The MMSE receiver has good performance and simple the realization concurrently.

As the MUD block diagram among Fig. 3 as seen, in linear multi-user detectors, demodulator output ym multiply by judgment variables wm, and this variable wm is used to optimize detector to judgement that sends symbol and the influence of eliminating channel.Under the situation of multi-user detector, for given one group of time delay τ K and attenuation parameter β km, select optimum weight matrix, so that the mean square error minimum of detector:

MSE(τ，β)＝E{(w ^Hy-b _k) ²} (1)

B wherein _kIt is k user's symbol.

MUD is not only applicable to a lot of cdma systems, and is applicable to other system, for example mimo system.Further information about background of the present invention is listed following, and is for reference when needing:

G.Orfanos，J.Habetha，L Liu，“MC-CDMA based IEEE802.11wirelessw LAN，”Proc.IEEE MASCOTS 2004，Oct.2004；

J.Proakis，Digital Communications.McGraw-Hill，Singapore，4thEdl，2001；

S.Hara，R.Prasad，“Overview of multicarrier CDMA，”IEEE Comm.Magazine，vol.35，issue 4，pp.104-108，April 1997；

B.Walke，Mobile Radio Networks.Willey & Sons Ltd，Chichester，Sussex，U.K.，2nd Ed.，2001；

J.Linnartz，“Performance analysis of synchronous MC-CDMA inmobile rayleigh channel both dealy and Doppler spreads，”IEEE Trans.On Vchicular Technology，vol.50，issue 6，Nov.2001；

IEEE 802.11 WG，Draft supplement to standard for informationtechnology telecommunications and information exchange betweensystems---LAN/MAN specific requirements---Part 11：Wirelessmedium acess control(MAC)and physical layer(PHY)specifications：High-speed physical layer in the 5 GHz band，IEEE Std.802.11a，1999；

F.Schreiber，“Effective Control of Simulation Runs by a NewEvaluation Algorithm for Correlated Random Sequences，”in AEUInternational Journal of Electronics and Communications，vol.42，no.6，pp.347-354，1988；

B.Walke，Mobifunknetze and ihre Protokolle，Stuttgart，Germany：B.G.Teuner，Band2，2.Auflage，2000；

D.Qiao，S.Choi，A.Jain，K.Shin，“Adaptive Transmit PowerControl in IEEE 820.11a Wireless LANs，”in Proc. IEEE VTC2003-Spring，April 2003；

M.Lott，Entwurf eines drahtlosen multihop Ad-hoc-Funknetzes mit

PhD Thesis，Mainz，Germany：AachenerBeitrage zur Mobil-und Telekommunikation，2001；

K.Wang，P.Zong，Y.Bar-Ness，“A reduced complexity partialsampling MMSE receiver for asynchronous MC-CDMA systems，”IEEEProc.GLOBECOM’01，2001；and

S.Yi，C.Tsimenidis，O.Hinton，B.Sharif，“Adaptive minimum biterror rate mulit-user detection for asynchronous MC-CDMA systems infrequency selective rayleigh fading channels，”IEEE Proc.PIMRC 2003，Sept.7-10，2003.

Summary of the invention

Embodiments of the invention comprise a kind of method that dynamically judgement is and current transmission walks abreast and sends or select another channel to send in communication network.This communication network comprises a plurality of equipment, comprising a data flow transmitter, the receiver that also comprises a data packet stream, this transmitter to its transmitting power of major general is indicated to this receiver of data stream receiver and is calculated the average interference rank of at least one previous packet by multi-user detector, and this receiver calculates the maximum transmission power of the maximum SINR that can realize, permission according to its disturbed condition and from the path loss of transmitted from transmitter to receiver; If the SINR that the maximum that calculates above can realize is less than the SINR of current transmission expection, this receiver decision changes frequency; Specific probability P of this receiver foundation is accomplished to the conversion of another channel, changes channel concurrently with radio station, the side of avoiding interference; Perhaps with probability 1-P and the parallel transmission of current transmission; Receiver informs that by using the little value in the frame duration territory transmitter frequency changes; Receiver is coded in channel id in the duration field of this frame.

In addition, embodiments of the invention comprise that the use packet exchanged current radio station transmitting power and disturbed condition information emission machine and receiver before Frame and/or Frame itself; Signaling packet is according to the RTS of IEEE 802.11 standards (being ready for sending) and CTS (permitting sending) bag, or according to bag or other management frames of the equivalence of revision standard (for example 802.11n) afterwards; The probability P of carrying out frequency inverted becomes big along with the increase of the quantity of the bag that triggers the frequency inverted program in receiver or the transmitter; Communication network uses the combination of MC-CDMA (MC-CDMA), multiple-input and multiple-output (MIMO), OFDM (OFDMA), time division multiple access (TDMA), frequency division multiple access (FDMA) or above-mentioned technology.

Above summary of the invention partly is not to show each embodiment of the present invention or various aspects.

Description of drawings

By with reference to following embodiment and accompanying drawing, can more fully understand method and apparatus of the present invention, wherein:

Fig. 1 is that spreading factor (SF) is 4 MC-CDMA system, can comprise embodiments of the invention;

Fig. 2 is based on the MAC agreement of MC-CDMA, and it uses the RTS/CTS access mechanism, can comprise embodiments of the invention;

Fig. 3 is the block diagram of MMSE receiver, can comprise embodiments of the invention;

Fig. 4 is based on the exemplary MAC RTS mac frame form of one embodiment of the invention;

Fig. 5 is based on the exemplary MAC RTS mac frame form of one embodiment of the invention;

Fig. 6 is flow chart and the exemplary algorithm according to the example frequency adaptation of one embodiment of the invention.

Embodiment

Code division multiple access (CDMA) network is subjected to the influence of near-far interference.For example, if use the receiver A of different spreading codes to be operated in simultaneously on the identical channel with transmitter B, then when receiver A is blocked by near transmitter B, near-far interference will appear.Embodiments of the invention provide a kind of mechanism or method to control parallel transmission amount among the MC-CDMA WLAN to avoid near-far interference.By the parallel transmission that provides a kind of mechanism or method to control different radio station among the MC-CDMAWLAN, can improve the performance of communication network, thereby realize transmission channel is utilized more efficiently, make that the throughput of signal is bigger, postpone lower.

Embodiments of the invention determine to disturb rank and SINR by means of MUD.The radio station use to disturb rank and/or SINR to judge it is move on to another channel to their communication link, still should continue on identical channel and current link parallel transmission.In exemplary embodiment, transmitter and receiver uses the frame of similar RTS and CTS to exchange information about transmitting power clearly.In another embodiment, the probability P of execution frequency inverted increases along with the increase of the bag quantity that triggers frequency inverted.

Following formula can be described the received signal in the asynchronous MC-CDMA system:

$r\left(t\right)=\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}\sqrt{a_k}{b}_k\underset{m=1}{\overset{M}{\mathrm{\&Sigma;}}}{c}_{\mathrm{km}}{h}_{\mathrm{<figure-callout\; id="2"\; label="km\; e\; j"\; filenames="S2006800159469E00021.png,S2006800159469E00041.png"\; state="\{\{state\}\}">km</figure-callout>}}{e}^j{2\mathrm{\&pi;}(t-{\mathrm{\&tau;}}_k)m/T}^{}p(t-{\mathrm{\&tau;}}_k)+\mathrm{\&eta;}\left(t\right)---\left(2\right)$

Wherein, K is the maximum activity number of users, a _kBe k user's symbol b _kTransmitting power, M is a sub-carrier number, p (t) is the rectangular pulse on [0, T], τ _kBe k user's delay, η (t) represents additive white Gaussian noise.M subcarrier and k user's Rayleigh decline process can be expressed from the next:

h _km＝β _kme ^jφkm(3)

β wherein _KmObey Rayleigh and distribute  _KmBe [0,2 π) obey equally distributed variable.

In this case, can calculate the SINR of MUD detector by following formula:

$\mathrm{SINR}=\frac{{\left|\sqrt{a_1}{w}^H{p}_{K+1}\right|}^2}{w^H\mathrm{\&Gamma;w}+{\left|w^H{P}_{K+1}{A}_{K+1}\right|}^2}---\left(4\right)$

Wherein matrix P and p are obtained by formula (1), and w is the weight vectors of MUD.

From formula (4) and obviously as can be known, by estimating the received power of other spreading code, use the radio station of four correlators can calculate the estimated value of SINR according to formula (4) from the analysis of formula 12 beginning.After estimating SINR, for known received power, MS can estimate the average interference at the packet reception period.

For the stability of implementation algorithm, each receiver utilizes following formula to calculate the average interference situation according to all bags that receive before:

$P_{\mathrm{MeanIF}}=\left\{\begin{array}{cc}{P}_{\mathrm{LastIF}},& P_{\mathrm{MeanIF}}=0\\ \mathrm{0,50}{P}_{\mathrm{MeanIF}}+0.50P_{\mathrm{LastIF}},& \mathrm{else}\end{array}\right.---\left(5\right)$

Because the frame that receives at last is near actual value, so in the end the interference during the received frame is weighted 0.5.Adopt this method of weighting, can avoid owing to experienced the channel switch that single bag caused of deep fade.Further, this algorithm can overcome near-far problem fast.Weight factor 0.5 is an example value, and this value can the working condition different with WLAN adapt.

In order to make the disturbance regime exchange between the different radio station become possible (the frequency adjustment algorithm need be disturbed alternately), utilize two extra territory Txpow52 and Ifpow54 (described) that RTS 50 and CTS 51 are expanded (exceeding the IEEE802.11a standard) as Fig. 4 and Fig. 5.Fig. 4 is a RTS frame 50 through expansion.Fig. 5 is a CTS frame 51 through expansion.In the Txpow52 territory, the transmitting power of present frame is encoded, Ifpow54 carries the latest estimated information about the average interference in this radio station on the channel that transfer of data takes place.The length in each territory is a byte.

Table 1: the parameter of adaptive algorithm

Parameter	Value
		P TX S1	The transmitting power of radio station S1
P TX S2	The transmitting power of radio station S2
		P IF S1	The average interference of S1 is estimated before the transmission RTS
P IF S2	The average interference of S1 is estimated before the transmission CTS
		P RX RTS	The received power of RTS frame among the S2
P RX CTS	The received power of CTS frame among the S1
		maxP TX	Maximum transmission power
newfreqID	The Id of new channel

Fig. 6 is frequency adaptation algorithm according to an embodiment of the invention or flow process Figure 60.Fig. 6 has provided the integral body of a frequency adaptation algorithm and has described.This algorithm is based on RTS-CTS-Data-Ack transmission circulation.Radio station 1 (S1) 62 expression transmitters, the corresponding receiver of radio station 2 (S2) 64 expressions.In addition, defined other variable that this algorithm needs in the table 1.Wherein all values all are that the form with dB provides.

Radio station S1 sends RTS frame 66 with the frame format of expanding among Fig. 4.In the RTS frame, be provided with and send P _TX ^S1And P _IF ^S1Currency.70, radio station S2 received power is P _RX ^RTSThe RTS frame and to P _TX ^S1And P _IF ^S1Value is decoded.At this moment, S2 can calculate the path loss L between S1 and the S2:

$L=P_{\mathrm{TX}}^{S1}-P_{\mathrm{RX}}^{\mathrm{RTS}}---\left(6\right)$

Then, consider the actual average Interference Estimation P of S2 _IF ^S2, path loss L and the maximum transmitting power that allows, S2 is that packet receives and calculates maximum possible SINR:

$\max \mathrm{SINR}=\max P_{\mathrm{TX}}-L-P_{\mathrm{IF}}^{S2}---\left(7\right)$

At this moment, radio station S2 just can judge at current disturbed condition S2 (P _IF ^S2) can wrap transmission down.

Two kinds of settings can be arranged:

First is provided with: max SINR＜min SINR

Wherein min SINR represents the thresholding that is provided with of needs, and according to the PHY pattern of using and the QoS target of link, for example, QoS is expressed as the form of the maximum Packet Error Ratio (PER) that can tolerate.In this case, radio station S2 64 carries out initialization with a specific probability to frequency inverted.Use healthy and strong BPSK1/2PHY pattern that the CTS frame 72 of expansion is sent to radio station S162.At territory P _TX ^S2And P _IF ^S2In fill out the currency of S2.

The duration of representing transfer of data behind the CTS frame end with the duration field in the CTS frame with the form of millisecond.Under the situation of frequency of occurrences conversion, because standard is not used the little value in the duration field, so S264 can use duration field to represent frequency inverted and new channel id is encoded.

After CTS frame 72 ends of transmission, S264 is transformed on the new channel 74 and all corresponding transmission parameters of resetting it:

${\mathrm{<figure-callout\; id="2"\; label="P\; TX\; S"\; filenames="S2006800159469E00021.png,S2006800159469E00041.png"\; state="\{\{state\}\}">P</figure-callout>}}_{\mathrm{TX}S}^2=\mathrm{start}{P}_{\mathrm{TX}}---\left(8\right)$

$P_{\mathrm{IF}}^{\mathrm{<figure-callout\; id="2"\; label="S"\; filenames="S2006800159469E00021.png,S2006800159469E00041.png"\; state="\{\{state\}\}">S</figure-callout>}2}=P_{\mathrm{NOISE}}=-93\mathrm{dBm}---\left(9\right)$

In order to forbid unnecessary frequency inverted and the conflict that in new channel, produces, need converted channel at random owing to near-far interference.If the traffic load between the radio station is very big, then the situation that may occur is: the receiver in a more than radio station is blocked mutually by the transmission in the transmission blocking in other radio station or each radio station.If a link between the radio station is transformed on another channel, then disturbed condition changes at once, and so all or most receiver can no longer be subjected to the influence of near-far interference.If not this situation, can take further frequency inverted.

In an embodiment of the present invention, above-mentioned random transition can realize by the following method: each radio station of calculating maximum SINR is with a certain probability inversion frequency, and this probability is set to 25% in the present embodiment.From other channel of system, determine the selection of new channel at random.

76, it is Rx-PowerP that S1 62 receives transmitting power _RX ^CTSThe CTS frame and from this frame, decode P _TX ^S2And P _IF ^S2Value.Correspondingly, S1 calculates the path loss between S1 and the S2:

$L=P_{\mathrm{TX}}^{S2}-P_{\mathrm{RX}}^{\mathrm{CTS}}---\left(10\right)$

The minimum SINR that under current disturbed condition, can obtain:

$\max \mathrm{SINR}=\max P_{\mathrm{TX}}-L-P_{\mathrm{IF}}^{S2}---\left(11\right)$

Maximum SINR value and minimum SINR value that S1 has calculated above are relatively determined frequency inverted.Because S2 is included in the information of frequency inverted in the duration field of CTS frame of expansion, thus do not need this step operation, but it provides another kind of controlling mechanism for this algorithm.S162 is transformed on the new channel 78 and resets according to formula (7) and formula (8) its P _TX ^S1And P _IF ^S1Parameter.Then, S162 unwraps once new transmission of beginning with a RTS on new channel.

Second is provided with: max SINR＞min SINR

Transfer of data 80 may occur on the current channel.It is P that S264 sends an actual value shown in Figure 2 _TX ^S2And P _IF ^S2The CTS frame 72 of expansion.As standard is described, comprise the duration of transfer of data behind the CTS frame end in the duration field.

If the correct frame of falling CTS that receives, S1 62 will send real packet 80 according to agreement so.If wrong situation about receiving, then the RTS retransmission timer of the MAC agreement of S1 will reach 0, so by increasing CW with the factor 2 in advance, S1 62 will unwrap starting weight with new RTS and pass trial.

In order further to support embodiments of the invention, methods and applications to provide following mathematics support.The received signal of n carrier wave can be expressed as:

$y_n=\frac{1}{T}\underset{T}{\overset{(i+1)T}{\text{\&Integral;}}}r\left(t\right)e^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="S2006800159469E00021.png,S2006800159469E00041.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;nt}/T}\mathrm{dt}---\left(12\right)$

In a linear multi-user detectors, the output y of demodulator _nMultiply by judgment variables w _n, w _nBe used for making detector the judgement optimization that sends symbol to be eliminated simultaneously the influence of channel.

${\hat{b}}_k=w^{H}y---\left(13\right)$

In the example of Fig. 3 MMSE MUD40, at given time delay τ _kWith the decline parameter beta _KmDown, select optimum weight matrix to make the mean square error minimum of detector, optimum weight matrix can be calculated by following formula:

MSE(τ，β)E{(w ^Hy-b _k) ²} (13)

Wherein bk is k user's a symbol.

Formula (12) can be expressed as:

$y_n=\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}\sqrt{a_k}[p_{\mathrm{nk}}{b}_k\left(i\right)+{\stackrel{\&OverBar;}{p}}_{\mathrm{nk}}{b}_k(i-1)]+{\mathrm{\&zeta;}}_n---\left(14\right)$

Wherein:

$p_{\mathrm{nk}}=\frac{1}{T}\underset{m=1}{\overset{M}{\mathrm{\&Sigma;}}}{c}_{\mathrm{km}}{h}_{\mathrm{km}}{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="S2006800159469E00021.png,S2006800159469E00041.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}{\mathrm{n\&tau;}}_k/T}\underset{{\mathrm{\&tau;}}_k}{\overset{\mathrm{<figure-callout\; id="2"\; label="T\; e\; j"\; filenames="S2006800159469E00021.png,S2006800159469E00041.png"\; state="\{\{state\}\}">T</figure-callout>}}{\text{\&Integral;}}}{e}^j{2\mathrm{\&pi;}(m-n)t/T}^{}\mathrm{dt}---\left(15\right)$

${\stackrel{\&OverBar;}{p}}_{\mathrm{nk}}=\frac{1}{T}\underset{m=1}{\overset{M}{\mathrm{\&Sigma;}}}{c}_{\mathrm{km}}{h}_{\mathrm{km}}{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="S2006800159469E00021.png,S2006800159469E00041.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}{\mathrm{n\&tau;}}_k/T}\underset{0}{\overset{{\mathrm{\&tau;}}_{\mathrm{<figure-callout\; id="2"\; label="k\; e\; j"\; filenames="S2006800159469E00021.png,S2006800159469E00041.png"\; state="\{\{state\}\}">k</figure-callout>}}}{\text{\&Integral;}}}{e}^j{2\mathrm{\&pi;}(m-n)t/T}^{}\mathrm{dt}---\left(16\right)$

${\mathrm{\&zeta;}}_n=\frac{1}{T}\underset{0}{\overset{T}{\text{\&Integral;}}}\mathrm{\&eta;}\left(t\right)e^{-2\mathrm{\&pi;nt}/T}\mathrm{dt}---\left(17\right)$

Can derive analytical form by analysis mode (15):

$p_{\mathrm{nk}}=\frac{1}{T}\underset{m=1}{\overset{M}{\mathrm{\&Sigma;}}}\frac{c_{\mathrm{km}}{\mathrm{\&beta;}}_{\mathrm{km}}(T-{\mathrm{\&tau;}}_k)}{T}\left\{\cos \right[\left(\frac{{2\mathrm{\&pi;n\&tau;}}_k}{T}\right)-{\mathrm{\&phi;}}_{\mathrm{km}}]-j\sin [\left(\frac{{2\mathrm{\&pi;n\&tau;}}_k}{T}\right)-{\mathrm{\&phi;}}_{\mathrm{km}}\left]\right\}---\left(18\right)$

This formula can be used for (17).The formal description of the available matrix of formula (15):

y(i)＝PAb(i)+ξ(i) (19)

Wherein:

y(i)＝[y ₁，...y _k] ^T

$A=\mathrm{diag}[\sqrt{a_1},...,\sqrt{a_k},\sqrt{a_1},...,\sqrt{a_k}]---\left(20\right)$

b(i)＝[b ₁(i-1)，...，b _k(i-1)，b ₁(i)，...，b _k(i)]

ζ(i)＝[ζ ₁，...，ζ _M] ^T (22)

Wherein ξ represents that covariance matrix is Γ _{M * M}=σ _n ²The white Gaussian noise vector of I.

Like this, embodiments of the invention for based on the WLAN of MC-CDMA, based on CDMA's or the radio station in other multi channel wireless system a kind of method is provided, be used for dynamically judging being and current transmission parallel transmission, still select another channel in the communication system.Embodiments of the invention are fit to based on the cdma wireless system that uses MUD very much.In the embodiments of the invention, use MUD to estimate the estimator that the signal on the same channel disturbs.It is that its communication link is transformed on another channel that the radio station can judge in distributed situation, still parallel with current communication link continuation on same channel.

Embodiments of the invention can be applicable to other system with parallel communications stream, and for example many input majorities go out (MIMO) and OFDM (OFDMA) system.The Interference Estimation amount of the embodiment of the invention is not to be provided by MUD, also can by the channel measurement result in the radio station or mobile station calculate when being in idle condition.Also it will be appreciated that, be used to realize that the example protocol of the embodiment of the invention can be based on IEEE802.11a (a kind of wlan standard, it has carried out some and has revised, thereby can support exemplary CDMA physical layer (PHY Layer)) medium access control (MAC) agreement.

Above-described invention and method have diversified embodiment and variation.Shown in the accompanying drawing with embodiment described in just the present invention and the specific embodiment of method, but should be understood that, the invention is not restricted to the disclosed embodiments, but can not depart under the situation that defines and list inventive concept in claims, can carry out other reorganization, modification, alternative.Therefore should be understood that, protection scope of the present invention and overall understanding of the present invention contained above all schemes, and it is limited by following claims.

Claims (15)

1. in wireless multichannel communication network (38), a kind ofly dynamically judge it is to send data or select another channel (6a, 6b, 6c, 6d) to send the method for described data with other current transmission is parallel by radio station (62,64) in described multichannel communication network, described method comprises:

In a packet (66), indicate current power level by sending station (62) to receiving radio station (64);

Calculate the average interference rank of at least one previous packet that (70) receive from described sending station by described reception radio station (64);

By described reception radio station according to the obtainable maximum SINR of described interference level calculation;

If described obtainable maximum SINR less than acceptable minimum SINR, then changes (74) to another channel by described reception radio station (64);

To notify described sending station (62) to the described conversion (74) of described another channel by described reception radio station (64), described notice is that the lining, a territory (66,72) one of at least in RTS bag and CTS wrap provides.

2. the method for claim 1, wherein described conversion comprises:

For fear of on described another channel, clashing, be transformed on described another channel with probability P with described other current transmission.

3. the method for claim 1 also comprises:

By described reception radio station the channel ID of described another channel is coded in the described duration field one of at least in RTS frame (50) and the CTS frame (51).

The method of claim 1, wherein at described sending station before described reception radio station sends Frame, in the packet that described sending station provides, carry out described indicating.

5. the method for claim 1, wherein in a Frame (66), carry out described indicating by described sending station (62).

6. the method for claim 1, wherein described RTS bag (66) and described CTS (72) bag are followed at least a IEEE 802.11 standards basically.

7. the method for claim 1, wherein described multichannel communication network is to use the network of at least a technology in MC-CDMA, MIMO, OFDMA, FDMA, SDMA and the TDMA technology.

8. a multi-channel wireless network (38) comprising:

Be arranged in a plurality of radio station (62,64) of described multi-channel wireless network, wherein, having a radio station at least is sending station (62), and having another radio station at least is to receive radio station (64);

Described reception radio station (64) comprises a MUD (40), described reception radio station is according to the signal judged result from described MUD, determine that signal disturbs rank and relevant SINR (70), described reception radio station is also partly according to described SINR, judges whether the link between it and the described sending station is transformed on the one other channel (70).

9. multi-channel wireless network as claimed in claim 8, wherein, at least one in RTS frame (50,66) and the CTS frame (51,72) used in described reception radio station, and exchange is about the information of transmitting power.

10. multi-channel wireless network as claimed in claim 9, wherein, described RTS frame and CTS frame all comprise at least one in transmitting power territory (TxPow) (52) and the interference power territory (IfPow) (54) separately.

11. multi-channel wireless network as claimed in claim 8, wherein, described network uses at least a in MC-CDMA, MIMO, OFDMA, SDMA, FDMA and the TDMA technology.

12. a kind of transceiver of multi-channel wireless network (62,64), described transceiver comprises:

Receiver module (66,70) receives radio communication information from sending station;

Determination module (70) is determined the SINR of described radio communication information, and described determination module comprises a MUD (40);

Judge module (70) if described SINR is lower than predetermined rank, judges whether described transceiver should be transformed into communication link on another channel;

Communication module (72) communicates with described sending station, and the channel ID of described another channel is provided.

13. transceiver as claimed in claim 12, wherein, described transceiver is used in the multi-channel wireless network (60), and described wireless network uses at least a in MC-CDMA, MIMO, SDMA, FDMA, TDMA and the OFDMA technology.

14. transceiver as claimed in claim 12, wherein, described transceiver is the part of travelling carriage.

15. transceiver as claimed in claim 12, wherein, described wireless network uses a kind of agreement, and this agreement is based on a kind of MAC agreement of IEEE 802.11 standards.

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