CN1474608A - Signal transmitting and receiving method based on time-division duplexing in radio communication system - Google Patents

Abstract

This invention discloses a method for signal emitting and receiving based on time-division duplex, setting many antennas at the basestation side and mobile station side separately, the said antennas are designed on the principle that noises received on each antenna are mutual independent, thus, the mobile station measures received signals on its own side receive antennas and selects one as the up-line emitting antenna to take it as the emitting antenna at the next up-line emitting time. The base station selects one antenna as the downstream emitting antenna from multiantenna at its side receiving signals from the mobile stations and emits signals to the mobile at the next time, increasing transmission efficiency of high speed data and getting the maximum high S/N ratio.

Description

Signal based on time division duplex in the wireless communication system transmits and receives method

Technical field

The signal that the present invention relates in the wireless communication system transmits and receives method.

Background technology

Radio communication provides the means that connect and obtain information whenever and wherever possible each other for people, has therefore obtained popularizing rapidly in recent years.Yet in present wireless environment, because the demand that moves, the directional transmissions of wireless signal has certain restriction, so just causes the radio communication of different user to exist inevitably each other and interferes with each other.In order to guarantee normally carrying out of various radio communications, the use of wireless frequency spectrum generally all will be subjected to strict restriction and management, radio communication can not have very big bandwidth as wire communication like this, therefore, based on limited available radio spectrum, how can increase the wireless communication system message transmission capability is the problem that presses for solution.

In radio communication, the wireless channel of decline is one of principal element that hinders the efficient communication realization.For this reason, the researcher has proposed the technology of many antenna emission/receptions, " under fading environment; when using the radio communication multilayer of multiple element antenna empty structure (G J Foschini; " Layered space-timearchitecture for wireless communication in fading environment when usingmulti-element antennas "; Bell Labs Technical Journal; pp.41-59; Autumn1996.) disclose above-mentioned technology in the literary composition; this technology can guarantee high efficiency high speed data transfer communication under independently flat fading channel is supposed.Yet because the influence that radio communication is disturbed each other, the Signal to Interference plus Noise Ratio that many antennas receive is also not really high; In addition, because a plurality of channels of wireless receiving can not keep separate at any time, in the unit interval of each reception, still disturb mutually, add factors such as the mutual coupling of antenna, the problem that the method that many antennas are launched simultaneously/received still exists efficient seriously to be reduced in realization.

Summary of the invention

The object of the present invention is to provide that the signal based on time division duplex transmits and receives method in a kind of wireless communication system, use this method can improve the efficiency of transmission of high-speed data, and obtain high as far as possible letter at signal receiving end and do (making an uproar) ratio.

For achieving the above object, the signal based on time division duplex in the wireless communication system provided by the invention transmits and receives method, comprises the steps:

Step 1: in base station side and mobile station side a plurality of antennas are set respectively, the principle setting that the noise that described a plurality of antennas receive according to each antenna is separate;

Step 2: the received signal on the different reception antennas of this side of moving table measuring, a selected antenna wherein is as up transmitting antenna, at the up x time of the next one, with this selected antenna as transmitting antenna, up transmitting in up launch time section;

Step 3: the base station is according to the signal of the travelling carriage that receives on many antennas of this side, and a selected antenna wherein as the downlink antenna, in next downlink constantly, transmits to travelling carriage in the time period in downlink.

Received signal on the different antennae of the described moving table measuring of step 2 is the pilot signal of base station, also can be the broadcast singal of base station, can also be the dedicated channel signal of base station to this travelling carriage emission.

Selected antenna wherein described in step 2 and the step 3 is selective reception signal strength signal intensity or the highest antenna of signal to noise ratio.

The many same signals of antennas emission of base station side when the channel strong correlation of many aerial signals of base station side, are selected simultaneously in the described base station of step 3 when transmitting, by different antennae being done different weightings, realize the directional transmissions of this signal.

The separate principle setting of noise that the described a plurality of antennas of step 1 receive according to each antenna, for base station side, between adjacent antenna the distance more than or equal to

For mobile station side, the distance between the adjacent antenna is not less than

Wherein, a is the serving sector angle of base station, and λ is a carrier wavelength.

Also the distance between the adjacent antenna of base station side and mobile station side all can be set to more than or equal to 1/2 carrier wavelength.

The present invention adopts antenna single transmit, the method that receives to carry out transmitting and receiving of wireless signal more, compare with existing many antenna emissions, method of reseptance, do not need the separate condition of a plurality of signaling channels, therefore environment that can be practical is more extensive, can be applied in diversity antenna and smart antenna.In addition, owing to the employing single-antenna transmission, the phase mutual interference that transmits reduces, and not only receive to handle simply, can obtain dried (making an uproar) ratio of high as far as possible letter, and the signal energy efficiency of transmission is higher, therefore is more suitable for using in wireless environment.In addition, therefore the inventive method does not have the signal of multiple transmit antennas to carry out synchronous demand on reception antenna owing to adopt single-antenna transmission, is easier to realize.

Embodiment

In existing multiaerial system, the prerequisite of its application is to have independently rayleigh fading channel.Because the diversity of actual environment, when reception antenna at a distance of being a half of carrier wavelength, still might there be bigger correlation in the fading channel that signal experienced.Yet, for noise, because the incoming wave azimuthal distribution of noise signal is in whole 0 to 360 degree space, in addition, noise signal in the wireless environment generally is the synthetic of a plurality of unlike signals, therefore, more than or equal to for half two antennas of carrier wavelength, its noise that receives is separate basically for distance each other.

With two reception antennas is example, and when its noise that receives was separate, for the transmitting of single transmit antenna, the received signal on two reception antennas can be represented by following expression: Wherein, r ₁And r ₂Be respectively the received signal on antenna 1 and the antenna 2, S is the symbol of single-antenna transmission, and the conventional letter energy is E _S, h ₁And h ₂The fading channel that is experienced when then being two reception antennas of this symbol arrival respectively, n ₁And n ₂It then is the noise that two antennas receive.

Transmit and receive the method for wireless signal according to existing many antennas, suppose h ₁And h ₂Be the flat fading channel of known (perhaps estimating), and in the short time that signal receives, be constant or (not the requiring that here two channels are separate) of slow variation, and suppose the noise n that two antennas receive ₁And n ₂Be Gaussian noise, noise power is σ ²Can know from the discussion of front, when two antennas at a distance of a half that surpasses carrier wavelength, these two noise signals are separate.The received signal of antenna is carried out high specific merges, the signal after then merging: $r=h_1^{*}{r}_1+h_2^{*}{r}_2=({\left|h_1\right|}^2+{\left|h_2\right|}^2)S+(h_1^{*}{n}_1+h_2^{*}{n}_2)---\left(2\right)$ The signal to noise ratio of the signal that obtains is: $\mathrm{SNR}=\frac{{({\left|h_1\right|}^2+{\left|h_2\right|}^2)}^2{E}_S}{{\left|h_1\right|}^2{\mathrm{\σ}}^2+{\left|h_2\right|}^2{\mathrm{\σ}}^2}=({\left|h_1\right|}^2+{\left|h_2\right|}^2)\frac{E_S}{{\mathrm{\σ}}^2}---\left(3\right)$

Originally the signal to noise ratio of two reception antennas is respectively ${\left|h_1\right|}^2\frac{E_S}{{\mathrm{\σ}}^2},{\left|h_2\right|}^2\frac{E_S}{{\mathrm{\σ}}^2},$ Then by formula (3) as can be known, the signal to noise ratio of received signal has obtained enhancing.Because the enhancing undesired signal channel of signal to noise ratio is condition independently, and only needs the separate condition of noise; This condition is met in wireless environment easily, for example, when many antennas are set, as long as different antennae can be met substantially at a distance of half that surpasses carrier wavelength, no matter is in base station side, still at mobile terminal side.

Below enforcement of the present invention is described in further detail.

In based on TDD radio communication system, at first a plurality of antennas are set respectively in base station side and mobile station side, the principle setting that the noise that above-mentioned a plurality of antenna receives according to each antenna is separate, specifically can adopt following method setting: the antenna phase mutual edge distance of base station side, can decide according to the sector angle a size of service, make the distance of adjacent two antennas be not less than carrier wave half-wavelength * 360 degree/a, promptly between adjacent antenna the distance more than or equal to Also can simply be set to half of carrier wavelength; The distance of the adjacent antenna of travelling carriage one side then not should less than carrier wavelength half, promptly the distance between the adjacent antenna more than or equal to Travelling carriage is when receiving base station broadcast information, can detect the intensity of the signal that many reception antennas receive, in up emission, with the strongest that antenna of the detected signal of previous moment as transmitting antenna, transmit uplink signal in up launch time section, this signal can be the pilot signal of base station, also can be the broadcast singal of base station, can also be the dedicated channel signal of base station to this travelling carriage emission.The base station can be with the strongest that antenna of the received signal that judges as the downlink antenna after receiving the transmitting of user, downlink in the time period to user's transmitting downstream data.No matter in base station side, still at mobile station side, an above-mentioned selected transmit antennas is the highest or the highest antenna of signal to noise ratio (signal interference ratio) of selective reception signal strength signal intensity.Certainly, the selection of single transmit antenna also can be selected according to other principle.

The method of the invention is not got rid of the use of base station intelligent antenna.The base station is in downlink, if there is the situation of relevant fully or strong correlation in many antennas, also can realize directional transmissions with these many antennas.Because in directional transmissions, the signal of many antenna emissions is identical, the channel that is experienced is also basic identical, and difference only is the difference of weighted value, thereby forms the directional transmissions on the space, so its effect still is equal to the single antenna emission.

Claims (8)

1, the signal based on time division duplex transmits and receives method in a kind of wireless communication system, comprises the steps:

Step 1: in base station side and mobile station side a plurality of antennas are set respectively, the principle setting that the noise that described a plurality of antennas receive according to each antenna is separate;

Step 2: the received signal on the different reception antennas of this side of moving table measuring, a selected antenna wherein as up transmitting antenna, at the up x time of the next one,, transmits in the section in up launch time as transmitting antenna with this selected antenna;

Step 3: the base station is according to the signal of the travelling carriage that receives on many antennas of this side, and a selected antenna wherein as the downlink antenna, in next downlink constantly, transmits to travelling carriage in the time period in downlink.

2, transmit and receive method according to the signal based on time division duplex described in the claim 1, it is characterized in that: the received signal on the different antennae of the described moving table measuring of step 2 is the pilot signal of base station.

3, transmit and receive method according to the signal based on time division duplex described in the claim 1, it is characterized in that: the received signal on the different antennae of the described moving table measuring of step 2 is the broadcast singal of base station.

4, transmit and receive method according to the signal based on time division duplex described in the claim 1, it is characterized in that: the received signal on the different antennae of the described moving table measuring of step 2 is the dedicated channel signal of base station to this travelling carriage emission.

5, transmit and receive method according to claim 1,2,3 or 4 described signals based on time division duplex, it is characterized in that: the selected antenna wherein described in step 2 and the step 3 is selective reception signal strength signal intensity or the highest antenna of signal to noise ratio.

6, transmit and receive method according to the signal described in the claim 5 based on time division duplex, it is characterized in that: the described base station of step 3 is when transmitting, when the channel strong correlation of many aerial signals of base station side, select the many same signals of antenna emission of base station side simultaneously, by different antennae being done different weightings, realize the directional transmissions of this signal.

7, transmit and receive method according to the signal described in the claim 6 based on time division duplex, it is characterized in that: the separate principle setting of noise that the described a plurality of antennas of step 1 receive according to each antenna, for base station side, between adjacent antenna the distance more than or equal to For mobile station side, the distance between the adjacent antenna more than or equal to Wherein, a is the serving sector angle of base station, and λ is a carrier wavelength.

8, transmit and receive method according to the signal described in the claim 6 based on time division duplex, it is characterized in that: the separate principle setting of noise that the described a plurality of antennas of step 1 receive according to each antenna, the distance between the adjacent antenna of base station side and mobile station side more than or equal to

Wherein, λ is a carrier wavelength.