CN101242210A - Transmit diversity system and method, transmitter and extended code allocating method - Google Patents

Transmit diversity system and method, transmitter and extended code allocating method Download PDF

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CN101242210A
CN101242210A CNA2008100049991A CN200810004999A CN101242210A CN 101242210 A CN101242210 A CN 101242210A CN A2008100049991 A CNA2008100049991 A CN A2008100049991A CN 200810004999 A CN200810004999 A CN 200810004999A CN 101242210 A CN101242210 A CN 101242210A
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code
wave
signal
wave beam
space
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藤井正明
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Samsung Electronics Co Ltd
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Samsung Electronics Co Ltd
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Abstract

The invention provides a transmit diversity system, method and extending code distribution method. A transmit diversity system comprises: a transmitter for coding transmitting signal space as space coding signal, executing a time domain expansion and frequency domain expansion of the space coding signal to generate the extending signal and transmitting the extending signal after distributing the extending signal to the wave beam spaces of a plurality of wave beams according to the feedback information received from the receiver; a code distribution device distributing the extending code related to zero deflection in the time domain expansion according to the feedback information if a single beam used by a user is included in a plurality of wave beams used by another user or if a plurality of wave beams used by a user is used by another user.

Description

Transmit diversity systems and method, transmitter and extended code allocating method
The application be that April 26, application number in 2004 are 200410095921.7 the applying date, denomination of invention divides an application for the application for a patent for invention of " transmit diversity systems and method ".
Technical field
Usually, the present invention relates to a kind of transmit diversity systems, method and computer program product, it can adopt the OFDM code division multiplexing (OFDM-CDM) of carrying out two-dimensional expansion (being time domain and frequency domain), relates more specifically to a kind of space-time transmit diversity systems and transmitting antenna array that uses in mobile communication system.
Background technology
Figure 13 is a block diagram of describing the space-time transmit diversity techniques that uses space-time (ST) sign indicating number, this paper " A simple Transmit Diversity Technique For WirelessCommunication " at S.M.Alamouti, IEEE Journal on Selected Areas In Communications, Vol.16, No.8, pp1451-1458 proposes among the October1993.According to the transmit diversity techniques of Alamouti, for two transmit symbol s 1, s 2, the 2x2 orthogonal space-time sign indicating number matrix that is produced at the space-time code device 1330 shown in Figure 13 is provided by equation 1:
Ω = s 1 s 2 - s 2 * s 1 *
At moment t1, from first antenna, 1301 emission s emission signal s 1And simultaneously from second antenna, 1302 emission s emission signal s 2At moment t2, transmit-s from first antenna 1301 2 *And transmit-s from second antenna 1302 simultaneously 1 *
With reference to Figure 13, the channel response of " h1 " expression from first antenna 1301 to terminal 1303, and the channel response of " h2 " expression from second antenna 1302 to terminal 1303.Signal r in moment t1 and t2 reception 1And r 2Respectively by equation 2 and 3 expressions:
r 1＝h 1s 1+h 2s 2 (2)
r 1＝-h 1s 2 *+h 2s 1 * (3)
Receiver in terminal 1303 is based on decoding to received signal from the channel response h1 of first antenna 1301 with from the channel response h2 of second antenna 1302, and decoded signal is represented with equation 4 and 5 respectively:
s ^ 1 = h 1 * r 1 + h 2 r 2 * = ( | h 1 | 2 + | h 2 | 2 ) s 1 - - - - ( 4 )
s ^ 2 = h 2 * r 1 - h 1 r 2 * = ( | h 1 | 2 + | h 2 | 2 ) s 2 - - - ( 5 )
From the signal of decoding, may detect s emission signal s 1 and s2, and may realize that also high specific merges.
Figure 14 to 16 explanation is a kind of to be used for selecting to improve by optimum beam the transmit diversity techniques of emission characteristics, this M.Fujii " paper " Beamspace-Time Transmit Diversity ForTime-Domain Spreading OFDM-CDM Systems "; IEICE Trans.onCommunications; Vol.E86-b; No.1; pp.344-351 proposes among the January 2003.
In the transmit diversity techniques that uses optimum beam to select, fixing a plurality of wave beams are used in the base station.And each travelling carriage is estimated the channel response from each of a plurality of wave beams, with the power (for example, adding the power of all subcarriers in the multi-carrier scheme) that calculates each wave beam.Then, mobile station in selecting provide the maximum channel responding power and two adjacent beams (or a pair of adjacent beams), and representing the wave beam of these two selected wave beams that index is sent to the base station.In this transmit diversity techniques, transmitter carries out space-time code to using 2x2 orthogonal space-time encoder matrix to the signal that will launch, and gives two specified wave beams of base station the signal allocation of space-time code.In addition, use the OFDM-CDM that only carries out the time domain expansion that the signal that is formed the weighting of array weight vector by wave beam is expanded.Multiplexing this spread signal and other subscriber signals then.
In addition, receiver is carried out the time domain despreading, suppressing all signals of other users, thus the signal of decoding expectation.
Figure 17 has illustrated in existing space-time transmit diversity systems how to give extended area the signal allocation of space-time code.1701 pairs of emissions of space-time code device data are carried out space-time code, to export the signal [s of two space-time codes 1, s 2] and [s 2 *,-s 1 *].Signal [the s of these two space-time codes 1, s 2] and [s 2 *,-s 1 *] carried out beam rider guidance respectively by beam direction vector (beam steering vector) 1702 and 1703 successively, in adder 1704, be re-used then.
Two signal (s from adder 1704 outputs 1W B1+ s 2W B2,-s 2 *W B1+ s 1 *W B2) at two extended area (2xSF Time) time domain (or at time orientation) in the expansion.For the orthogonality between the code that maintains the time domain despreading, spreading factor has to be limited to the degree that does not influence the channel variation in the time domain.For the time idle bit, require channel response should not rely on and change at the slot length of a large amount of code elements of time domain output.Therefore, implement this design and must make there is not the influence that changes in the time domain on two extended areas.But if the time domain spreading factor is limited to be lower than predetermined value, the number of users that can hold will reduce so.In addition, if the free influence that changes on two extended areas, emission characteristics will worsen so.
In two above-mentioned beam selection methods,, thereby improve emission characteristics if the user between two adjacent beams shown in Figure 180, so just can obtain the beam diversity gain.If the user is positioned near the maximum gain of wave beam shown in Figure 19, and corresponding electromagnetic angle expansion (angular spread) is narrower than the width of wave beam, so just can obtain beam gain.But, although used a plurality of wave beams, in fact have only the signal of a beam transmission to arrive travelling carriage (corresponding to the user), therefore can waste the signal power that can distribute to other wave beams.
According to above-mentioned space-time transmit diversity techniques, when only transmitting when time domain is expanded, all signals except this subscriber signal all are suppressed in the despreading of receiver.For example, if many users use different wave beams right, but one of right two wave beams of each wave beam are shared by different users, and the signal of different user can disturb each other when idle bit was decoded so at that time.Therefore, at receiver user, can suppress all signals of other users by the time domain despreading, thereby prevent interference.
But, according to the two-dimensional expansion of carrying out all time domain expansions and frequency domain expansion, when to a wave beam when right during the idle bit decoding, (in the two-dimensional expansion zone) can not suppress to distribute to the right time idle bit and distributing to and time interference between the idle bit that described wave beam is right to other wave beams of a shared wave beam of wave beam in the despreading of time domain part.For example, as shown in figure 20, when the first and second wave beam #1 and #2 are used for user #1, and when the second wave beam #2 and the 3rd wave beam #3 are used for user #2, if the signal that is transmitted into user #1 is with (s1 s2) represents, and is transmitted into the signal (s3 of user #2, s4) expression is used h from the first and second wave beam #1 and #2 respectively to the channel response on m subcarrier of user #1 M, 1And h M, 2Expression, the signal that is received m subcarrier first user can be provided by equation 6 and 7 so.
r m，1＝h m，1s 1+h m，2s 2+h m，2s 3 (6)
r m，2＝-h m，1s 2 *+h m，2s 1 *-h m，2s 4 * (7)
The signal r that is received M, 1And r M, 2Use channel response h M, 1And h M, 2Decode, and the signal of being decoded can be represented with equation 8 and 9.
s ^ m , 1 = h m , 1 * r m , 1 + h m , 2 r m , 2 * = ( | h m , 1 | 2 + | h m , 2 | 2 ) s 1 + h m , 1 * h m , 2 s 3 - | h m , 2 | 2 s 4 - - - ( 8 )
s ^ m , 2 = h m , 2 * r m , 1 - h m , 1 r m , 2 * = ( | h m , 1 | 2 + | h m , 2 | 2 ) s 2 + | h m , 2 | 2 s 3 + h m , 1 h m , 2 * s 4 - - - ( 9 )
As shown in second and the 3rd of the right of equation, two-dimensional expansion can cause the interference between signals of user #1 and #2.
Correspondingly, for the time domain extended method,, therefore also can suppress other users' signal, and can not cause interference by despreading because this method uses channel response to be considered to the constant interior extended code of scope.But according to this two-dimensional expansion method, differing on each subcarrier in the partial correlation between the extended code is decided to be zero, thereby causes distracter recited above.Because the decoding item of subscriber signal and response item (| h M, 1| 2+ | h M, 2| 2) difference, also can not remove distracter fully even therefore carry out the frequency domain combination.
Summary of the invention
Therefore, consider that above-mentioned problem designs the present invention, and an object of the present invention is to provide a kind of transmit diversity systems, method and program product, its two-dimensional expansion OFDM-CDM is used multi-beam and the time idle bit transmit diversity techniques in can to channel the time become and frequency selectivity provides fabulous resistance.
According to a first aspect of the invention, the top purpose with other can realize that this transmit diversity systems comprises by a transmit diversity systems: transmitter is used for launching this signal afterwards giving the beam space of multi-beam signal allocation; Receiver, the channel estimating that is used to receive these a plurality of wave beams and obtains each wave beam of a plurality of wave beams; First choice device is used for selecting wave beams right from a plurality of wave beam centerings of a plurality of wave beams, selected wave beam to have corresponding to the maximum power of the channel estimating separately of two right wave beams of described wave beam and; And second choice device, if the difference between the power of the channel estimating separately of two wave beams of selected wave beam centering greater than predetermined value, is then selected two wave beams one from selected wave beam centering.
According to a second aspect of the invention, system according to first aspect is provided, if the difference between the power of the channel estimating separately of two wave beams of wherein selected wave beam centering is greater than predetermined value, second choice device is selected one from two right wave beams of selected wave beam, selected this power of channel estimating in these two wave beams is greater than another the power of channel estimating in these two wave beams.
According to a third aspect of the invention we, a kind of transmit diversity systems is provided, comprise: transmitter, being used for the signal space-time code that will launch is the space-time code signal, carry out the time domain expansion of this space-time code signal and frequency domain expansion producing spread signal, and behind the beam space of this spread signal being distributed to multi-beam, launch this spread signal; And assignment of code device, if if one of a plurality of wave beams that one of a plurality of wave beams that in the single wave beam that user uses and a plurality of wave beams that another user uses one is identical or user uses and another user use are identical, then be distributed in the extended code that time domain has 0 partial correlation in expanding.
According to a forth aspect of the invention, provide the system according to the third aspect, wherein this assignment of code device also is distributed in the extended code that has 0 partial correlation in the time domain expansion in addition and gives the right user of a plurality of use same beam.
According to a fifth aspect of the invention, a kind of receiver is provided, be used to receive the signal of the beam space of distributing to a plurality of wave beams and obtain the channel estimating of each wave beam of these a plurality of wave beams, described receiver comprises first choice device, be used for selecting wave beams right from a plurality of wave beam centerings of these a plurality of wave beams, selected wave beam to have corresponding to the maximum power of the channel estimating separately of two right wave beams of described wave beam and; And second choice device, if the difference between the power of the channel estimating separately of two wave beams of selected wave beam centering greater than predetermined value, is then selected one from two right wave beams of selected wave beam.
According to a sixth aspect of the invention, a kind of transmitter is provided, be used for estimating from the receiver receive channel, described receiver is used to receive the signal of the beam space of distributing to a plurality of wave beams and obtains the channel estimating of each wave beam of these a plurality of wave beams, described transmitter comprises first choice device, be used for selecting wave beams right from a plurality of wave beam centerings of these a plurality of wave beams, selected wave beam to have corresponding to the maximum power of the channel estimating separately of two right wave beams of described wave beam and; And second choice device, if the difference between the power of the channel estimating separately of two wave beams of selected wave beam centering greater than predetermined value, is then selected two wave beams one from selected wave beam centering.
According to a seventh aspect of the invention, a kind of transmitter is provided, being used for the signal space-time code that will launch is the space-time code signal, carry out the time domain expansion of this space-time code signal and frequency domain expansion with the generation spread signal, and this spread signal of emission behind the beam space of this spread signal being distributed to multi-beam, described transmitter comprises: the assignment of code device, if if one of a plurality of wave beams that one of a plurality of wave beams that in the single wave beam that user uses and a plurality of wave beams that another user uses one is identical or user uses and another user use are identical, then be distributed in the extended code that time domain has 0 partial correlation in expanding.
According to an eighth aspect of the invention, provide the transmitter according to the 7th aspect, wherein this assignment of code device also is distributed in the extended code that time domain expansion has 0 partial correlation in addition and gives the right user of a plurality of use same beam.
According to a ninth aspect of the invention, a kind of beam selection method in transmit diversity systems is provided, this transmit diversity systems comprises transmitter and receiver, this transmitter is this signal of emission after distributing signal is given a beam space of a plurality of wave beams, this receiver receives these a plurality of wave beams and obtains the channel estimating of each wave beam of these a plurality of wave beams, said method comprising the steps of: a) select wave beams right from a plurality of wave beam centerings of these a plurality of wave beams, selected wave beam to have corresponding to the maximum power of the channel estimating separately of two right wave beams of described wave beam and; And b) if the difference between the power of the channel estimating separately of two wave beams of selected wave beam centering greater than predetermined value, is then selected two wave beams one from selected wave beam centering.
According to the tenth aspect of the invention, method according to the 9th aspect is provided, wherein said step b) comprises: if the difference between the power of the channel estimating separately of two wave beams of selected wave beam centering is greater than predetermined value, just select one from two right wave beams of selected wave beam, selected this power of channel estimating in these two wave beams is greater than another the power of channel estimating in these two wave beams.
According to an eleventh aspect of the invention, a kind of extended code allocating method in transmit diversity systems is provided, this system comprises transmitter, being used for the signal space-time code that will launch is the space-time code signal, carry out the time domain expansion of this space-time code signal and frequency domain expansion with the generation spread signal, and this spread signal of emission behind the beam space of this spread signal being distributed to multi-beam, said method comprising the steps of:, then be distributed in the extended code that time domain has 0 partial correlation in expanding if if one of a plurality of wave beams that one of a plurality of wave beams that in the single wave beam that user uses and a plurality of wave beams that another user uses one is identical or user uses and another user use are identical.
According to a twelfth aspect of the invention, a kind of extended code allocating method in transmit diversity systems is provided, this system comprises transmitter, being used for the signal space-time code that will launch is the space-time code signal, carry out the time domain expansion of this space-time code signal and frequency domain expansion with the generation spread signal, and this spread signal of emission behind the beam space of this spread signal being distributed to multi-beam said method comprising the steps of: be distributed in the time domain expansion and have the extended code of 0 partial correlation to the right user of a plurality of use same beam.
According to a thirteenth aspect of the invention, a kind of recording medium that comprises the beam selection program is provided, this program is used for making receiver to carry out a kind of beam selection method at transmit diversity systems, described receiver receives the signal of the beam space of distributing to a plurality of wave beams and obtains the channel estimating of each wave beam of these a plurality of wave beams, said method comprising the steps of: select wave beams right from a plurality of wave beam centerings of these a plurality of wave beams, selected wave beam to have corresponding to the maximum power of the channel estimating separately of two right wave beams of described wave beam and; And if the difference between the power of the channel estimating separately of two wave beams of selected wave beam centering is then selected one greater than predetermined value from two right wave beams of selected wave beam.
According to a fourteenth aspect of the invention, a kind of recording medium that comprises the beam selection program is provided, this program is used for making transmitter to carry out a kind of beam selection method at transmit diversity systems, described transmitter is estimated from the receiver receive channel, this receiver receives the signal of the beam space of distributing to a plurality of wave beams and obtains the channel estimating of each wave beam of these a plurality of wave beams, said method comprising the steps of: select wave beams right from a plurality of wave beam centerings of these a plurality of wave beams, selected wave beam to have corresponding to the maximum power of the channel estimating separately of two right wave beams of described wave beam and; And if the difference between the power of the channel estimating separately of two wave beams of selected wave beam centering is then selected one greater than predetermined value from two right wave beams of selected wave beam.
According to a fifteenth aspect of the invention, a kind of recording medium that comprises the beam selection program is provided, this program is used for making transmitter to carry out a kind of beam selection method at transmit diversity systems, described transmitter is the signal space-time code that will launch the space-time code signal, carry out the time domain expansion of this space-time code signal and frequency domain expansion with the generation spread signal, and this spread signal of emission behind the beam space of this spread signal being distributed to multi-beam, said method comprising the steps of:, then be distributed in the extended code that time domain has 0 partial correlation in expanding if if one of a plurality of wave beams that one of a plurality of wave beams that in the single wave beam that user uses and a plurality of wave beams that another user uses one is identical or user uses and another user use are identical.
According to a sixteenth aspect of the invention, provide the medium according to the 15 aspect, wherein said method further comprises step: being distributed in time domain expansion, to have partial correlation be that 0 extended code is given the right user of a plurality of use same beam.
According to a seventeenth aspect of the invention, provide a kind of transmit diversity systems to comprise: transmitter, being used for the signal space-time code that will launch is the space-time code signal, carry out the time domain expansion of this space-time code signal and frequency domain expansion producing spread signal, and behind the beam space of this spread signal being distributed to multi-beam, launch this spread signal; The beam allocation device is used for distributing the space-time code signal to give a plurality of wave beams of these a plurality of wave beams in the spatial domain; And the extended code distributor, be used for distributing the space-time code signal of time domain to a plurality of extended codes in same extended area.
According to an eighteenth aspect of the invention, system according to the 17 aspect is provided, wherein this beam allocation device selects wave beams right from a plurality of wave beam centerings of a plurality of wave beams of receiver reception, selected wave beam to have corresponding to the maximum power of the channel estimating separately of two right wave beams of described wave beam and, if and the difference between the power of the channel estimating separately of two wave beams of selected wave beam centering is greater than predetermined value, this beam selection device from corresponding to select right two wave beams of selected wave beam one and distribute the space-time code signal in this spatial domain give in these two wave beams selected this.
According to a nineteenth aspect of the invention, system according to the 17 aspect is provided, if if wherein one of a plurality of wave beams of one of a plurality of wave beams that in the single wave beam that uses of user and a plurality of wave beams that another user uses is identical or user uses and another user's use are identical, then this extended code distributor is distributed in the extended code that has 0 partial correlation in the same extended area.
According to a twentieth aspect of the invention, system according to the 18 invention is provided, wherein the wave beam in the following manner this beam allocation device selected of this extended code distributor is to being categorized as wave beam to group, this mode makes the wave beam that does not disturb each other to being classified as same wave beam group, and wave beam interfering with each other is to being classified as different wave beams to group, and the extended code distributor distributes the extended code of the two-dimensional expansion factor to give different wave beams to group, and described extended code is that the different branches from the time domain extension layer of expansion code tree branch away.
According to a twenty-first aspect of the invention, system according to the 19 aspect is provided, wherein the wave beam in the following manner this beam allocation device selected of this extended code distributor is to being categorized as wave beam to group, this mode makes the wave beam that does not disturb each other to being classified as same wave beam group, and wave beam interfering with each other is to being classified as different wave beams to group, and the extended code distributor distributes the extended code of the two-dimensional expansion factor to give different wave beams to group, and described extended code is that the different branches from the time domain extension layer of expansion code tree branch away.
According to a twenty-second aspect of the invention, system according to the tenth eight aspect is provided, wherein this extended code distributor extended code of distributing the two-dimensional expansion factor is to described in selected two wave beams of beam allocation device one, and described extended code is that the different branches from the time domain extension layer of expansion code tree separate.
According to a twenty-third aspect of the invention, system according to the 19 aspect is provided, wherein this extended code distributor extended code of distributing the two-dimensional expansion factor is to described in selected two wave beams of beam allocation device one, and described extended code is that the different branches from the time domain extension layer of expansion code tree separate.
According to a twenty-fourth aspect of the invention, a kind of emission diversity method in transmit diversity systems is provided, this transmit diversity systems comprises: transmitter, being used for the signal space-time code that will launch is the space-time code signal, carry out the time domain expansion of this space-time code signal and frequency domain expansion with the generation spread signal, and this spread signal of emission behind the beam space of this spread signal being distributed to multi-beam said method comprising the steps of: a) distribute the space-time code signal to give a plurality of (plurality) wave beam of a plurality of (multiple) wave beam in the spatial domain; And b) the space-time code signal in the distribution time domain is given a plurality of extended codes in same extended area.
According to the twenty-fifth aspect of the invention, method according to the 25 aspect is provided, if wherein corresponding to the difference between the power of the channel estimating separately of two right wave beams of the wave beam of a plurality of wave beam centerings selections of this a plurality of wave beams that receive from receiver greater than predetermined value, then from be assigned to corresponding to the space-time code signal of selecting one and spatial domain right two wave beams of selected wave beam in these two wave beams selected this, wherein selected wave beam to have corresponding to the maximum power of the channel estimating separately of two right wave beams of described wave beam and.
According to the twenty-sixth aspect, method according to the 24 aspect is provided, if, then be distributed in the extended code that has 0 partial correlation in the same extended area if wherein one of a plurality of wave beams of one of a plurality of wave beams that in the single wave beam that uses of user and a plurality of wave beams that another user uses is identical or user uses and another user's use are identical.
According to a twenty-seventh aspect of the invention, method according to the 25 aspect is provided, if, then be distributed in the extended code that has 0 partial correlation in the same extended area if wherein one of a plurality of wave beams of one of a plurality of wave beams that in the single wave beam that uses of user and a plurality of wave beams that another user uses is identical or user uses and another user's use are identical.
According to a twenty-eighth aspect of the invention, method according to the 25 aspect is provided, wherein in the following manner have maximum power and wave beam to be categorized as wave beam to the group, this mode makes the wave beam that does not disturb each other to being classified as same wave beam group, and wave beam interfering with each other is to being classified as different wave beams to group, and the extended code of distributing the two-dimensional expansion factor gives different wave beams to group, and described extended code is that the different branches from the time domain extension layer of expansion code tree branch away.
According to the twenty-ninth aspect, method according to the 26 aspect is provided, wherein in the following manner have maximum power and wave beam to be categorized as wave beam to the group, this mode makes the wave beam that does not disturb each other to being classified as same wave beam group, and wave beam interfering with each other is to being classified as different wave beams to group, and the extended code of distributing the two-dimensional expansion factor gives different wave beams to group, and described extended code is that the different branches from the time domain extension layer of expansion code tree branch away.
According to a thirtieth aspect of the invention, method according to the 27 aspect is provided, wherein in the following manner have maximum power and wave beam to be categorized as wave beam to the group, this mode makes the wave beam that does not disturb each other to being classified as same wave beam group, and wave beam interfering with each other is to being classified as different wave beams to group, and the extended code of distributing the two-dimensional expansion factor gives different wave beams to group, and described extended code is that the different branches from the time domain extension layer of expansion code tree branch away.
According to a thirty-first aspect of the invention, method according to the 25 aspect is provided, the extended code of wherein distributing the two-dimensional expansion factor is to one of described in selected two wave beams of beam allocation device, and described extended code is that the different branches from the time domain extension layer of expansion code tree branch away.
According to a thirty-second aspect of the invention, method according to the 26 aspect is provided, the extended code of wherein distributing the two-dimensional expansion factor is to one of described in selected two wave beams of beam allocation device, and described extended code is that the different branches from the time domain extension layer of expansion code tree branch away.
According to the 33 aspect of the present invention, method according to the 27 aspect is provided, the extended code of wherein distributing the two-dimensional expansion factor is to one of described in selected two wave beams of beam allocation device, and described extended code is that the different branches from the time domain extension layer of expansion code tree branch away.
According to the 34 aspect of the present invention, a kind of computer-readable recording medium that comprises signal procedure is provided, this program is used to make transmit diversity systems to carry out a kind of emission diversity method, this transmit diversity systems comprises: transmitter, being used for the signal space-time code that will launch is the space-time code signal, carry out the time domain expansion of this space-time code signal and frequency domain expansion with the generation spread signal, and this spread signal of emission behind the beam space of this spread signal being distributed to multi-beam said method comprising the steps of: a) distribute the space-time code signal to give a plurality of wave beams of these a plurality of wave beams in the spatial domain; And b) the space-time code signal in the distribution time domain is given a plurality of extended codes in same extended area.
According to the 35 aspect of the present invention, medium according to the 34 aspect is provided, if wherein in the method corresponding to the difference between the power of the channel estimating separately of two right wave beams of the wave beam of a plurality of wave beam centerings selections of this a plurality of wave beams that receive from receiver greater than predetermined value, then from being assigned to one of described in these two wave beams corresponding to the space-time code signal of selecting one and this spatial domain right two wave beams of selected wave beam, wherein selected wave beam to have corresponding to the maximum power of the channel estimating separately of two right wave beams of described wave beam and.
According to the 36 aspect of the present invention, medium according to the 34 aspect is provided, if, then be distributed in the extended code that has 0 partial correlation in the same extended area if wherein one of a plurality of wave beams of one of a plurality of wave beams that in the single wave beam that uses of user and a plurality of wave beams that another user uses is identical or user uses in the method and another user's use are identical.
According to the 37 aspect of the present invention, medium according to the 35 aspect is provided, if, then be distributed in the extended code that has 0 partial correlation in the same extended area if wherein one of a plurality of wave beams of one of a plurality of wave beams that in the single wave beam that uses of user and a plurality of wave beams that another user uses is identical or user uses in the method and another user's use are identical.
According to the 30 eight aspect of the present invention, medium according to the 35 aspect is provided, wherein in the method in the following manner have maximum power and wave beam to be categorized as wave beam to the group, this mode makes the wave beam that does not disturb each other to being classified as same wave beam group, and wave beam interfering with each other is to being classified as different wave beams to group, and the extended code of distributing the two-dimensional expansion factor gives different wave beams to group, and described extended code is that the different branches from the time domain extension layer of expansion code tree branch away.
According to the 39 aspect of the present invention, medium according to the 36 aspect is provided, wherein in the method in the following manner have maximum power and wave beam to be categorized as wave beam to the group, this mode makes the wave beam that does not disturb each other to being classified as same wave beam group, and wave beam interfering with each other is to being classified as different wave beams to group, and the extended code of distributing the two-dimensional expansion factor gives different wave beams to group, and described extended code is that the different branches from the time domain extension layer of expansion code tree branch away.
According to the 40 aspect of the present invention, medium according to the 35 aspect is provided, the extended code of wherein distributing the two-dimensional expansion factor in the method is to described in selected two wave beams of beam allocation device one, and described extended code is that the different branches from the time domain extension layer of expansion code tree branch away.
According to the of the present invention the 40 on the one hand, method according to the 36 aspect is provided, the extended code of wherein distributing the two-dimensional expansion factor in the method in selected two wave beams of beam allocation device described this, described extended code is that the different branches from the time domain extension layer of expansion code tree branch away.
Description of drawings
From detailed description, more being expressly understood above the present invention below in conjunction with accompanying drawing with other purposes, characteristics and advantage, in the accompanying drawings:
Fig. 1 is the configuration block diagram of expression according to the closed loop beam selection device in the travelling carriage of the first embodiment of the present invention;
Fig. 2 is the block diagram of explanation according to the base station of the first embodiment of the present invention;
Fig. 3 is the concept map of explanation according to a kind of two-dimensional expansion of the present invention;
Fig. 4 illustrates according to the first embodiment of the present invention, produces and distribute the concept map of extended code when selecting two wave beams;
Fig. 5 illustrates according to the first embodiment of the present invention, produces and distribute the concept map of extended code when selecting single or multiple wave beam;
Fig. 6 is the block diagram of explanation according to the travelling carriage of the first embodiment of the present invention;
Fig. 7 is that explanation produces when selecting two wave beams according to the first embodiment of the present invention and the distribution extended code is given the concept map of subscriber signal and pilot signal;
Fig. 8 is the chart of explanation according to the spread signal frame of the first embodiment of the present invention;
Fig. 9 is the chart of explanation according to the fixed beam pattern with low secondary lobe of the first embodiment of the present invention;
Figure 10 is the configuration block diagram of the closed loop beam selection device in the travelling carriage that illustrates according to a second embodiment of the present invention;
Figure 11 is the block diagram that base station according to a second embodiment of the present invention is described;
Figure 12 is how explanation carries out a kind of space-time emission diversity method in base station according to a second embodiment of the present invention a concept map;
Figure 13 is the block diagram of the existing transmit diversity systems of explanation;
Figure 14 is the block diagram that explanation is used for the existing space-time diversity system of time domain OFDM-CDM;
Figure 15 is the block diagram of the receiver of the explanation existing space-time diversity system that is used for time domain OFDM-CDM;
Figure 16 is the block diagram of the existing closed loop wave beam of explanation to selector;
Figure 17 illustrates that the signal that how to distribute space-time code in the prior art gives the concept map of extended area;
Figure 18 is explanation at customer location and concept map with the relation between the wave beam zone of wide angle expansion;
Figure 19 is explanation at customer location and concept map with the relation between the wave beam zone of narrow angle expansion;
Figure 20 be two users of explanation use corresponding wave beam to and the concept map of the example of a shared wave beam.
Embodiment
Describe wave beam space-time transmit diversity systems according to a preferred embodiment of the invention with reference to the accompanying drawings in detail.
In the accompanying drawings, the identical or similar elements of same reference numerals is even they are in different accompanying drawings.
First embodiment
Fig. 1 is the block diagram of explanation according to the wave beam space-time transmit diversity systems of the first embodiment of the present invention.Wave beam space-time transmit diversity systems according to first embodiment of the invention comprises travelling carriage (transceiver) 1 and base station (transceiver) 2.As shown in Figure 1, adopt a kind of closed loop beam selection scheme according to the wave beam space-time transmit diversity systems of the first embodiment of the present invention.
Travelling carriage 1 is equipped with closed loop beam selection device, it comprises antenna 10, switch 11, first to the 4th channel estimator 12-1 is to 12-4, first to the 4th power calculator 13-1 is to 13-4, and first to the 4th adder 14-1 is to 14-4, and maximum wave beam is to power and detector 15, power difference comparator 16, and list/multi-beam selector 17.Antenna 10 receives a plurality of wave beams (being first to the 4th wave beam in this embodiment) of transmitting antenna array 20 emissions from base station 2, and the signal that output receives is given switch 11, and emission is from the index of the selected wave beam of switch 11 inputs.
Switch 11 outputs to channel estimator 12-1 to the received signal from antenna 10 inputs to 12-4, and the index of the selected wave beam of importing from power comparator 16 is outputed to antenna 10.In addition, antenna 11 is according to controller (not shown) conversion I/O operator scheme.
Fast fourier transformer 60 receives by the received signal of antenna 10, and removes protection (GI) at interval after down-conversion from the signal that receives.Fast fourier transformer 60 is converted to sub-carrier signal to received signal by fast fourier transform, and sub-carrier signal, promptly first to the 4th wave beam outputs to channel estimator 12-1 respectively to 12-4.
Channel estimator 12-1 uses the extended code of each subcarrier that the sub-carrier signal from switch 11 inputs is carried out despreading to 12-4.From despread signal, remove the pilot signal modulation item to estimate channel response.Channel estimator 12-1 outputs to power calculator 13-1 to estimated channel response to 13-4 to 12-4.
Power comparator 13-4 calculates the power of the channel response of input from channel estimator 12-1 to 12-4 to 13-4, and the power addition on all subcarriers that calculate, to estimate from the corresponding power of wave beam and to export estimated power and give adder 14-1 to 14-4.Just, the estimating power P of the first power calculator 13-1 beamformer output #1 1To the first and the 4th adder 14-1 to 14-4.The estimating power P of the second power calculator 13-2 beamformer output #2 2To the first and second adder 14-1 to 14-2.The estimating power P of the 3rd power calculator 13-3 beamformer output #3 3To the second and the 3rd adder 14-2 to 14-3.The estimating power P of the 4th power calculator 13-4 beamformer output #4 4To the third and fourth adder 14-3 to 14-4.
Adder 14-1 is to the estimating power P of each first to the 4th wave beam of importing from power calculator 13-1 to 13-4 of 14-4 1To P 4In two corresponding power additions, and power and output to maximum wave beam to power and detector 15.Just, first adder 14-1 received beam #1 estimates P to the power of #2 1And P 2, and power and (P 1+ P 2) output to maximum wave beam to power and detector 15.Second adder 14-2 received beam #2 estimates P to the power of #3 2And P 3, and power and (P 2+ P 3) output to maximum wave beam to power and detector 15.The 3rd adder 14-3 received beam #3 estimates P to the power of #4 3And P 4, and power and (P 3+ P 4) output to maximum wave beam in power and the detector 15.The 4th adder 14-4 received beam #4 estimates P to the power of #1 4And P 1, and power and (P 4+ P 1) output to maximum wave beam to power and detector 15.
Maximum wave beam is to power and detector 15 receptions and compare four wave beams to power and P 1+ P 2, P 2+ P 3, P 3+ P 4And P 4+ P 1, with determine four wave beams to power and maximum.Maximum wave beam to power and detector 15 corresponding to the maximum wave beam of determining to power and wave beam index and this wave beam are estimated to output to power difference comparator 16 to the corresponding power of the wave beam of index representative.
Here, wave beam to index representative corresponding to wave beam to power and beam combination.For example, if power and P1+P2 be maximum power and, then corresponding wave beam index just is defined as the combination of representing wave beam #1 and #2 (wave beam #1, #2).For other wave beam to power and, define wave beam in an identical manner to index.
From maximum wave beam the power of power and detector 15 outputs is estimated it is corresponding to maximum wave beam the wave beam of power and detector 15 outputs to be estimated the power separately of a plurality of wave beams (being two wave beams in this embodiment) of index.For example, (wave beam #1 #2), then estimates it is that (wave beam #1, the power separately of a plurality of wave beams #2) is estimated P to index corresponding to wave beam from maximum wave beam to the power of power and detector 15 outputs to index if maximum wave beam is to power and detector 15 beamformer outputs 1And P 2
Power difference comparator 16 received beams estimate to the power separately of the wave beam of index representative that to index and this wave beam difference and predetermined threshold between relatively the power that is received is estimated are exported comparative result then and given this list/multi-beam selector 17.The comparative result of the difference between these list/multi-beam selector 17 received beams are estimated the power of a plurality of wave beams of index representative, select simple beam or multi-beam in a plurality of wave beams according to this comparative result, export then corresponding to the beam index of a selected wave beam or a plurality of wave beams and give switch 11.
If this power difference is equal to or greater than this predetermined threshold, then 17 of this lists/multi-beam selector are selected a wave beam having estimation of maximum power in a plurality of wave beams.But, if this power difference less than this predetermined threshold, then should list/multi-beam selector 17 these wave beams of selection to all a plurality of wave beams of index representative, promptly at wave beam to two wave beams in the index.
Fig. 2 is the block diagram of explanation according to the base station 2 of the first embodiment of the present invention.As shown in Figure 2, base station 2 comprises transmitting antenna array 20, error correcting encoder 21, and mapper 22, interleaver 23, space-time code device 24, antenna branch 25-1 is to 25-n (n is a natural number), and extended code dispensing controller 26.Error correcting encoder 21 receives the data that will launch, and after error correction coding these data is outputed to mapper 22.Mapper 22 receives the data of error correction coding, and in modulation constellation mapping back it is outputed to interleaver 23.Interleaver 23 receives mapped data and after data reordering it is outputed to space-time code device 24, and reordering here is in order to disperse burst error.
2x2 orthogonal space-time encoder matrix shown in the top equation 1 of space-time code device 24 usefulness carries out space-time code to the signal of interleaver output.Space-time code device 24 is the signal allocation of space-time code and output to a wave beam or a plurality of wave beam of the selection beam index representative that receives from travelling carriage 1.
In first embodiment, the wave beam that selected wave beam #1 and #2 are for example represented in base station 2 receptions is to index, and the signal that space-time code device 24 distributes space-time codes outputs to corresponding antenna branch 25-1 to 25-n then to wave beam #1 and #2.
Antenna branch 25-1 comprises multiplexer 30 to each of 25-n; piece S/P transducer 31, two-dimensional expansion device 32-1 is to 32-m (m is a natural number), other subscriber signal multiplexers 33; pilot signal multiplexer 34, and inverse fast Fourier transformer and protection at interval (=IFFT+GI) 35.
Multiplexer 30 receives the space-time code signal that space-time code devices 24 are distributed to the wave beam of selected beam index representative, and multiplexing and export this wave beam to piece S/P transducer 31.In first embodiment, for example, multiplexer 30 carries out multiplexing to the transmit symbol of space-time code by the respective array weight of transmitting antenna array 2, with multiplexing wave beam #1 and #2.
Piece S/P transducer 31 receives the code element with the multiplexing wave beam space-time code of wave beam #1 and #2, and is being that unit carries out the string of receiving symbol and code element that the output of conversion back receives gives two-dimensional expansion device 32-1 to 32-m with two code elements.
Two-dimensional expansion device 32-1 is to the 32-m reception and distribute the code element of the wave beam space-time code of going here and there and changing to give the expanding section shown in Fig. 3.Two-dimensional expansion device 32-1 uses the Walsh sign indicating number to 32-m at each expanding section, and with the two-dimensional expansion of execution on time and frequency domain or direction, and a signal of expansion outputs to other subscriber signal multiplexer 33.
With reference to Fig. 3, with the quantity (SF of the OFDM code element in the time domain Time) and frequency domain in the quantity (SF of subcarrier Freq) definition is as the two-dimensional expansion section of extended area.Two-dimensional expansion device 32-1 has a spreading factor (SF to what 32-m used that extended code dispensing controller 26 distributed TimeX SF Freq) extended code of (that is the time domain spreading factor x frequency domain expansion factor).Two-dimensional expansion device 32-1 carries out the time domain expansion to 32-m at first subcarrier, carries out the time domain expansion at the carrier wave adjacent with first subcarrier then.By repeating the time domain expansion by this way, two-dimensional expansion device 32-1 carries out two-dimensional expansion to 32-m in time domain and frequency domain.
Other subscriber signal multiplexers 33 are received in the transmit symbol of the wave beam space-time code of time domain and frequency domain two-dimensional expansion, and multiplexing a plurality of users' code element and export multiplexing data and give pilot signal multiplexer 34.The pilot signal of pilot signal multiplexer 34 temporal extension (or time domain expansion) wave beam, pilot signal and with the multiplexing growth data of other user's data carry out multiplexing, and multiplexing data output to inverse fast Fourier transformer 35.
IFFT+GI35 is converted to time-domain signal to the data that receive by invert fast fourier transformation (IFFT), and protection interval (GI) is added in the signal, carries out upconverting on the carrier frequency, then the signal of conversion is outputed to transmitting antenna array 20.Transmitting antenna array 20 comprises a plurality of respectively corresponding to the antenna (in this embodiment be n antenna) of antenna branch 25-1 to 25-n.A plurality of the transmitting that the corresponding IFFT+GI 35 of transmitting antenna array 20 emissions from antenna branch 25-1 to 25-n receives.
The single wave beam that uses as user is identical with one of a plurality of wave beams of another user's use, or one of a plurality of wave beams of using of one of a plurality of wave beams of using of user and another user are when identical, and extended code dispensing controller 26 is distributed in the time domain expansion provides the extended code of 0 partial correlation to these wave beams.In addition, when a plurality of users use same wave beam to the time, extended code dispensing controller 26 is distributed in the time domain expansion provides the extended code of 0 partial correlation to corresponding wave beam.The extended code that 26 outputs of extended code dispensing controller are distributed is given two-dimensional expansion device 32-1 each to 32-m.
Fig. 4 is how explanation extended code dispensing controller 26 distributes the concept map of extended code.With reference to Fig. 4, suppose and use wave beam (#1, user #2) and use wave beam to (#3, user #4) belong to group A, and use wave beam to (#2, user #3) and use wave beam to (#4, user #1) belong to group B.If suitably narrow to the expansion of the path angle of each terminal, then distribute to not interference between the right signal of different beams in same group by wave beam from the base station.In addition, when idle bit is decoded at that time, do not disturb each other at a plurality of users' of same wave beam centering signal, because these users use same wave beam right.But, (see equation 8 to 9) as mentioned above, belonging to not between the signal of different user on the same group has distracter.
In order to prevent distracter, in the following manner extended code is distributed to user's (or wave beam to).The extended code of the leaf that produces corresponding to the group node from a plurality of nodes that have identical time domain spreading factor (seeing " X " among Fig. 4) the Walsh shown in Fig. 4 expansion code tree is respectively distributed to the user that belongs to same group (or wave beam to).And corresponding to respectively from the different group nodes the Walsh shown in Fig. 4 expansion code tree (compare with time domain spreading factor X, be root or more near the node of root) produce not on the same group leaf not on the same group extended code distribute to the user who belongs to not on the same group.
In the example shown in Fig. 4,32 extended code 0-15 (seeing " A " among Fig. 4) are assigned to and belong to group A (promptly, use wave beam to (#1, user #2) and use wave beam are to (#3, user #4)) user, wherein 32 extended code 0-15 are from having a plurality of nodes X of same time domain spreading factor (seeing " X " Fig. 4) 1To X 8In a group node (X 1, X 2, X 3And X 4) leaf that produces respectively.32 extended code 16-31 (seeing " B " among Fig. 4) are assigned to and belong to group B (promptly, use wave beam to (#2, user #3) and use wave beam are to (#4, user #1)) user, wherein 32 extended code 16-31 are respectively from having a plurality of nodes X of same time domain spreading factor (seeing " X " Fig. 4) 1To X 8In a group node (X 5, X 6, X 7And X 8) leaf that produces.
Fig. 5 is a kind of method that is used to distribute extended code when selecting single or multiple wave beam of explanation.In Fig. 5, as at wave beam to as shown in the classification chart, suppose that the user organizes and be divided into group A, B and C, a plurality of wave beams are assigned to each user in A and B, single wave beam is assigned to each user in C.
As mentioned above, between same group user's signal, do not disturb.But belonging to not between the signal of different user on the same group has distracter (seeing equation 8 and 9).
Correspondingly, the extended code of the leaf that produces respectively corresponding to the same group node in a plurality of nodes that have identical time domain spreading factor (seeing " Y " among Fig. 4) from the Walsh shown in Fig. 5 expansion code tree is distributed to the user that belongs to same group (or wave beam to).Produce corresponding to never same group node respectively (root or more near the node of root) not on the same group leaf not on the same group extended code distribute to the user who belongs to not on the same group.
As shown in fig. 5,32 extended code 0-11 (seeing " A " among Fig. 5) are assigned to and belong to group A and (that is, use wave beam to (#1, user #2) and use the user of wave beam to (#3, user #4)).32 extended code 12-23 (seeing " B " among Fig. 5) are assigned to and belong to group B and (that is, use wave beam to (#2, user #3) and use the user of wave beam to (#4, user #1)).32 extended code 24-31 (seeing " C " among Fig. 5) are assigned to the user who belongs to group C (that is, use the user of the first wave beam #1, use the user of the second wave beam #2, use the user of the 3rd wave beam #3, use the user of the 4th wave beam #4).
In order to prevent between frequency domain Assemble Duration extended code, to disturb, be preferably that the basis will produce from the group node with identical time domain spreading factor not on the same group extended code (describing below) distribute to a plurality of users that use same beam team.
For example, in the example of Fig. 4, if a plurality of users select and use same wave beam to (#1, #2), just select extended code 0 to 15 for the user, because as mentioned above, the extended code of the generation of the group node from a plurality of nodes with identical time domain spreading factor (seeing " X " Fig. 4) is assigned to the wave beam that phase user on the same group uses.Here, from the identical group node with identical time domain spreading factor produce not on the same group extended code be assigned to a plurality of users' signal.For example, one group of extended code of priority allocation 0,4,8 and 12, and, distribute another group extended code 2,6,10 and 14 subsequently in a sequential manner along with the increase of number of users.
As shown in Figure 6; travelling carriage 1 comprises the space-time code device; comprise protection interval and fast fourier transform (GI+FFT) 60; time domain despreader 61-1 is to 61-n, and channel estimator 62-1,2 is to 62-n, 2n, and space-time decoder 63-1 is to 63-n; frequency domain combiner 64-1,2 is to 64-n, 2n; piece P/S transducer 65, deinterleaver 66, and error correction decoder 67.The signal that antenna 10 receives offers GI+FFT60.The signal of GI+FFT 60 down-conversions reception is removed protection at interval from received signal, be this conversion of signals sub-carrier signal by FFT, and exports this signal and arrive 62-n, 2n to 61-n and channel estimator 62-1,2 for time domain despreader 61-1.
Channel estimator 62-1, the 2 pilot signal phase modulation items to 62-n, 2n removal despread signal obtain channel response and estimate, and this estimation is outputed to space-time decoder 63-1 to 63-n.
Time domain despreader 61-1 receives sub-carrier signal to 61-n, and the duplicating of the pilot signal of using the extended code of pilot signal, pilot signal and resulting channel estimating to produce to receive from transmitting antenna.In addition, deduct duplicating of the pilot signal that received the sub-carrier signal of time domain despreader 61-1 to 61-n from Fourier transform, and the extended code of using the user distribute to travelling carriage 1 to the sub-carrier signal time despreading that received (promptly, despreading in time domain), wherein deducted pilot signal in the sub-carrier signal that is received.
Space-time decoder 63-1 uses the employed extended code of user of travelling carriage 1 to carrying out despreading from despreader sub-carrier signal output, the time despreading to 63-n.Space-time decoder 63-1 also uses channel estimating to carry out the time domain decoding of this signal to 63-n.The signal that frequency domain combiner 64-1,2 to 64-n, 2n decode to the space-time that receives from space-time decoder 63-1 to 63-n carries out combination of frequency (that is, making up) in frequency domain, and the signal of combination of frequency is outputed to piece P/S transducer 65.
65 pairs of combination of frequency signals that receive from frequency domain combiner 64-1,2 to 64-n, 2n of piece P/S transducer are carried out and the string conversion, and the signal of conversion is outputed to deinterleaver 66.Deinterleaver 66 receives from the switching signal of piece P/S transducer 65 outputs, and after the data with the mode reorder signal opposite with interleaver 23 signal that receives is outputed to error correction decoder 67.67 pairs of signals from deinterleaver 66 outputs of error correction decoder are carried out error correction decoding, with the data that obtain regenerating.
Referring now to the operation of accompanying drawing description according to the wave beam space-time transmit diversity systems of the first embodiment of the present invention.
As shown in Figure 1, if first to the 4th wave beam #1 is launched to #4 by transmitting antenna array 20 in base station 2, travelling carriage 1 passes through the wave beam #1 of antenna 10 reception emissions to #4, and by switch 11 wave beams that receive from antenna 10 is offered channel estimator 12-1 to 12-n.Channel estimator 12-1 to 12-n to the signal despreading that receives to estimate channel response, then estimated channel response is outputed to power calculator 13-1 to 13-4.
Power calculator 13-1 is to the power of 13-4 calculating channel response, and the power addition of calculating on all subcarriers, to estimate the power separately from wave beam.Adder 14-1 is to each responding power of channel estimating separately addition corresponding to two adjacent beams of each adder of 14-n, and these two channel response power and output to maximum wave beam to power and detector 15.
Four wave beams that maximum wave beam receives from four adder 14-1 to 14-n more respectively power and detector 15 to power and, with determine four wave beams to power and maximum.Maximum wave beam to power and detector 15 corresponding to determined maximum wave beam to power and wave beam index and this wave beam are estimated to output to power difference comparator 16 to the power separately of a plurality of wave beams of index representative.By this way, from a plurality of wave beams (being four in this embodiment), select to provide the maximum channel responding power and two adjacent beams.
Power difference comparator 16 obtains the difference between the power of channel response separately of two selected wave beams, and output is given list/multi-beam selector 17 about the information whether this difference is lower than predetermined threshold.More specifically, power difference comparator 16 received beams are estimated the power separately of a plurality of wave beams of index representative index and this wave beam, and difference and predetermined threshold between relatively institute's received power is estimated output to list/multi-beam selector 17 to this comparative result then.
If the power difference that power difference comparator 17 is calculated is lower than predetermined threshold, then list/multi-beam selector 17 is selected these two wave beams, if and this power difference is equal to or greater than predetermined threshold, then only select one of two wave beams to use as single wave beam, a selected wave beam is bigger than another power.In other words, list/multi-beam selector 17 receives the comparative result of this wave beam to the difference between the power estimation of a plurality of wave beams of index representative, from a plurality of wave beams, select single or multiple wave beams according to comparative result, and exporting to antenna 10 corresponding to the beam index of a selected wave beam or a plurality of wave beams by switch 11.Antenna 10 sends to base station 2 to this beam index.
Base station 2 execution error correction codings by interleaver 23, are shone upon the order of randomization data emission to the modulation signal point of launching data, and use the signal space-time code of orthogonal space-time encoder matrix to exporting from interleaver 23 of above-mentioned two row, two row.Correspondingly, base station 2 is given the signal allocation of space-time code from a wave beam or a plurality of wave beam of the selected beam index representative of travelling carriage 1 reception.
If travelling carriage 1 is specified a wave beam (that is, if simple beam has been selected in the representative of selected beam index), two of the index representative wave beams are identical so.Such beam index can have such as (#1, #1), (#2, #2), (#3, #3) or (#4, #4) such form.
Space-time transmit diversity systems recited above has the following advantages.The first, if orthogonal pilot signals is assigned to wave beam, if or pilot signal be re-used with after the orthogonal spreading code expansion, travelling carriage 1 (or recipient) can be estimated the channel response from each wave beam.
In addition, by the power of calculating channel estimation response, travelling carriage 1 can detect travelling carriage 1 residing beam area.
In addition, in first embodiment, base station 2 is given two adjacent beams or a simple beam signal allocation of the orthogonal space-time encoder matrix space-time code that is listed as with two row two.Travelling carriage 1 (or recipient) calculate from the power of the channel estimating of adjacent beams and, with detect representative provide maximum wave beam to power and the wave beam of two adjacent beams to index.
In addition, if big from the difference of the channel response power of travelling carriage 1 selected two wave beams, then travelling carriage can select one of two wave beams to use.In this case, selected beam index (that is beam selection information) is sent to the base station in up link.As a result, which wave beam base station 2 can be discerned and will distribute to each travelling carriage 1.
Suppose that wave beam is assigned to wave beam as Fig. 7 to group A shown in the classification chart and B, for example, if being the extended code of time domain spreading factor twice, spreading factor is assigned to a pilot signal, so, the extended code of the leaf that produces respectively corresponding to the group node in a plurality of nodes that have identical time domain spreading factor (seeing " Z " among Fig. 7) in the Walsh code tree is just distributed to the wave beam that uses on the same group mutually.Therefore be assigned to pilot signal because spreading factor is the extended code of two times of above time domain spreading factors, 16 extended codes 1 ' to 4 ' just are assigned to the pilot signal except group A and party B-subscriber's signal.
The sequence of symhols of two space-time codes is directed into a wave beam or a plurality of wave beam of travelling carriage appointment from a plurality of wave beams, and this sequence of symhols is multiplexing by wave beam then.The multiplexing sequence of symhols of wave beam is gone here and there and is changed at each transmission antenna branch, is assigned to expanding section then.At each expanding section, the Walsh sign indicating number is used for carrying out the two-dimensional expansion at time domain and frequency domain, and this code element and other users' signal multiplexing.Use is according to the extended code of a wave beam shown in Figure 7 to using.The pilot signal spreading factor that is used for each wave beam is that the extended code of time domain spreading factor twice is expanded in time domain, and is multiplexing with expanded data then.
As shown in Figure 8, each the expanding section (SF in Ns code element x Nc subcarrier scope (Ns is a number of symbols, and Nc is a number of subcarriers) TimeXSF Freq) after the expansion, pilot signal and other users' signal is re-used.
These sub-carrier signals are multiplexing and be converted to time-domain signal by invert fast fourier transformation (IFFT) by OFDM.In time-domain signal, add protection (GI) at interval, upconvert to carrier frequency then by transmitting antenna array 20 emissions (seeing the beam pattern of the fixed beam among Fig. 9).
Travelling carriage 1 (or recipient) is converted to the reception sub-carrier signal to the signal that receives by fast fourier transform.Use the despreading of extended code time to receive sub-carrier signal on each subcarrier, wherein the pilot signal of wave beam is assigned to described subcarrier.From despread signal, remove the pilot modulated item, from wave beam, to obtain channel estimating.
This user's extended code time despreading received signal is distributed in use, to suppress to cause the interference signals item.Next, signal is decoded by space-time, and makes up the signal of decoding at frequency domain.Despread signal is deinterleaved, then by error correction decoding, with the bit sequence that obtains regenerating.
As mentioned above, in existing extended code allocative decision, when idle bit was decoded at that time, shared common beam also used the right subscriber signal of different beams to disturb.In order to address this problem, consider that the extended code partial correlation that produces from same group node is 0, distribute the extended code that produces from same group node in the above described manner.This extended code is distributed makes receiver suppress the interference user signal by the time domain despreading.The present invention has an advantage, is exactly not disturb generation when idle bit was decoded at that time.
In addition, in extended code is distributed, from a plurality of nodes with identical time domain spreading factor produce not on the same group extended code preferably be assigned to and use the right a plurality of users of same beam.For example, one group of extended code of priority allocation 0,4,8 and 12, and, distribute another group extended code 2,6,10 and 14 in a sequential manner in succession along with number of users increases.This makes receiver can suppress other users' signal by the time domain expansion.Therefore, can prevent interference between frequency domain Assemble Duration extended code.
From top description obviously as can be seen, the wave beam space-time transmit diversity systems according to first embodiment of the invention also has the following advantages.In launch scenario, wherein in the OFDM-CDM system that adopts two-dimensional expansion, use emission multi-beam array in conjunction with space-time code, emission side carries out extended code and distributes, so as to make the recipient can by the time domain despreading the time idle bit suppress to cause interference signals when decoded, thereby prevent to disturb.Therefore, may improve emission characteristics and systematic function.
The first embodiment of the present invention has been described with reference to following situation, promptly in wave beam space-time transmit diversity systems, travelling carriage 1 estimate to produce selected beam index according to power, and base station 2 carries out extended code according to selected beam index and distribute control, but the present invention is not limited to this.For example, also may be that travelling carriage 1 calculating and sending is penetrated power and estimated to base station 2, and base station 2 be estimated to produce selected beam index according to this power and is carried out extended code according to selected beam index and distribute control.
Transmitter and receiver in travelling carriage and base station 1 and 2 all comprises computer system in each.Be used to carry out the said system operation, the program of selecting such as space-time code, space-time decoding and beam index can be stored in the computer readable recording medium storing program for performing with the form of program.Computer can be by reading in program stored executable operations in this medium.
For example, for each processing unit or element in the transmitter and receiver of operating or be implemented in above-mentioned travelling carriage and base station 1 and 2, in transmitter and receiver CPU (CPU) fetch program from such as the main storage of ROM or RAM in each, with executive program information processing and calculating.
Computer readable recording medium storing program for performing comprises disk, magneto optical disk, CD-ROM, DVD-ROM, semiconductor memory or the like.Such program also can be sent to computer by order wire, thereby computer can be carried out the program that is transmitted.
Second embodiment
Figure 10 is the block diagram that wave beam space-time transmit diversity systems according to a second embodiment of the present invention is described.As first embodiment, wave beam space-time transmit diversity systems according to a second embodiment of the present invention comprises travelling carriage (transceiver) 1 and base station (transceiver) 2, and adopts closed loop beam selection scheme.
Travelling carriage 1 is equipped with closed loop beam selection device, it comprises antenna 10, switch 11, first to the 4th channel estimator 12-1 is to 12-4, and first to the 4th power calculator 13-1 is to 13-4, and first to the 4th adder 14-1 is to 14-4, maximum wave beam is to power and detector 15, wave beam is to selector 18, power difference comparator 16, and list/multi-beam selector 17.
Antenna 10 receives a plurality of wave beams (being that first to the 4th wave beam #1 is to #4 in this embodiment) of transmitting antenna array 20 emissions from base station 2, and exports the signal that receives and give switch 11, and emission is from the index of the selected wave beam of switch 11 inputs.Switch 11 outputs to channel estimator 12-1 to the received signal from antenna 10 inputs to 12-4, and the index from list/selected wave beam that multi-beam selector 17 is imported is outputed to antenna 10.Antenna 11 is according to the control command conversion I/O operator scheme of controller (not shown).
GI+FFT 60 receives by the received signal of antenna 10, and removes protection (GI) at interval after down-conversion from the signal that receives.GI+FFT 60 is converted to sub-carrier signal to received signal by fast fourier transform, and sub-carrier signal, promptly first to the 4th wave beam outputs to channel estimator 12-1 respectively to 12-4.
Channel estimator 12-1 uses the extended code of each subcarrier that the sub-carrier signal from GI+FFT 60 inputs is carried out despreading to 12-4.From despread signal, remove the pilot signal modulation item to estimate channel response (following description).Channel estimator 12-1 outputs to power calculator 13-1 to estimated channel response to 13-4 to 12-4.
Power calculator 13-1 calculates the power of the channel response of input from channel estimator 12-1 to 12-4 to 13-4, and the power addition on all subcarriers that calculate, with estimate from the power separately of wave beam and export estimated power give adder 14-1 to 14-4 and wave beam to selector 18.Just, the estimating power P of the first power calculator 13-1 beamformer output #1 1To the first and the 4th adder 14-1 to 14-4 and wave beam to selector 18.The estimating power P of the second power calculator 13-2 beamformer output #2 2To the first and second adder 14-1 to 14-2 and wave beam to selector 18.The estimating power P of the 3rd power calculator 13-3 beamformer output #3 3To the second and the 3rd adder 14-2 to 14-3 and wave beam to selector 18.The estimating power P of the 4th power calculator 13-4 beamformer output #4 4To the third and fourth adder 14-3 to 14-4 and wave beam to selector 18.
Adder 14-1 is to the estimating power P of each first to the 4th wave beam of importing from power calculator 13-1 to 13-4 of 14-4 1To P 4In two corresponding power additions, and power and output to maximum wave beam to power and detector 15.In other words, first adder 14-1 received beam #1 estimates P to the power of #2 1And P 2, and power estimation and (P 1+ P 2) output to maximum wave beam to power and detector 15.Second adder 14-2 received beam #2 estimates P to the power of #3 2And P 3, and power estimation and (P 2+ P 3) output to maximum wave beam to power and detector 15.The 3rd adder 14-3 received beam #3 estimates P to the power of #4 3And P 4, and power estimation and (P 3+ P 4) output to maximum wave beam to power and detector 15.The 4th adder 14-4 received beam #4 estimates P to the power of #1 4And P 1, and power estimation and (P 4+ P 1) output to maximum wave beam to power and detector 15.
Maximum wave beam is to power and detector 15 receptions and compare four wave beams to power and P 1+ P 2, P 2+ P 3, P 3+ P 4And P 4+ P 1, with determine four wave beams to power and maximum.Maximum wave beam to power and detector 15 corresponding to the maximum wave beam of determining to power and wave beam index is outputed to power difference comparator 16.
Here, wave beam to index representative corresponding to wave beam to power and beam combination.For example, if power and P1+P2 be maximum power and, then corresponding wave beam index just is defined as the combination of representing wave beam #1 and #2 (wave beam #1, #2).For other wave beam to power and, define wave beam in an identical manner to index.
Wave beam to selector 18 from power calculator 13-1 to 13-4 received power estimate p 1To p 4, from maximum wave beam to received beam power and the detector 15 to index, and export this wave beam and the corresponding power of a plurality of wave beams (this example is two) of index representative estimated difference power comparator 16 to index with by this wave beam.
From maximum wave beam the power of power and detector 15 outputs is estimated it is corresponding to maximum wave beam the wave beam of power and detector 15 outputs to be estimated the power separately of a plurality of wave beams (being two wave beams in this embodiment) of index.For example, (wave beam #1 #2), estimates it is that (wave beam #1, the power separately of a plurality of wave beams #2) is estimated P to index corresponding to wave beam from maximum wave beam to the power of power and detector 15 outputs so to index if maximum wave beam is to power and detector 15 beamformer outputs 1And P 2
Power difference comparator 16 received beams estimate to the power separately of a plurality of wave beams of index representative that to index and this wave beam difference and predetermined threshold between relatively the power that is received is estimated are exported comparative result then and given this list/multi-beam selector 17.
The comparative result of the difference between list/multi-beam selector 17 received beams are estimated the power of a plurality of wave beams of index representative, select a simple beam or a plurality of wave beam in a plurality of wave beams according to this comparative result, export then corresponding to the beam index of a selected wave beam or a plurality of wave beams and give switch 11.If this power difference is equal to or greater than this predetermined threshold, then 17 of this lists/multi-beam selector are selected a wave beam having estimation of maximum power in a plurality of wave beams.But, if this power difference less than this predetermined threshold, then should be selected this wave beam all a plurality of wave beams to the index representative by list/multi-beam selector 17.
Figure 11 is the block diagram that base station according to a second embodiment of the present invention is described.As shown in figure 11, base station 2 comprises transmitting antenna array 20, error correcting encoder 21, and mapper 22, interleaver 23, space-time code device 24, antenna branch 25-1 is to 25-n (n is a natural number), and extended code dispensing controller 26.Error correcting encoder 21 receives the data that will launch, and after error correction coding these data is outputed to mapper 22.Mapper 22 receives the data of error correction coding, and in modulation constellation mapping back it is outputed to interleaver 23.Interleaver 23 receives mapped data and after data reordering it is outputed to space-time code device 24.
2x2 orthogonal space-time encoder matrix shown in the top equation 1 of space-time code device 24 usefulness carries out space-time code to the signal of interleaver 23 outputs.Space-time code device 24 is exported the signal of space-time code behind a wave beam or a plurality of wave beam of the signal allocation of space-time code being given the selected beam index representative that receives from travelling carriage 1.
In a second embodiment, the wave beam that selected wave beam #1 and #2 are for example represented in base station 1 reception is to index, and the signal that space-time code device 24 distributes space-time codes outputs to corresponding antenna branch 25-1 to 25-n then to wave beam #1 and #2.
Antenna branch 25-1 comprises multiplexer 30 to each of 25-n, S/P transducer 31,39-1 and 39-2, two-dimensional expansion device 32-1,2 to 32-m, 2m (m is a natural number), multiplexer 40, other subscriber signal multiplexers 36, pilot signal multiplexer 34, and invert fast fourier transformation (=IFFT+GI) 35.
Multiplexer 30 receives the space-time code signal that space-time code devices 24 are distributed to the wave beam of selected beam index representative, and multiplexing and output to piece S/P transducer 31 this wave beam.In this embodiment, for example, multiplexer 30 carries out multiplexing to the transmit symbol of space-time code by the respective array weight of transmitting antenna array 20, with multiplexing two wave beam #1 and #2.
S/P transducer 31 receives and the multiplexing wave beam space-time code code element of a plurality of wave beams (being two in this embodiment), and in the string and the conversion back that with two code elements are unit execution receiving symbol two signals is outputed to S/P transducer 39-1 and 39-2.From two signals of S/P transducer 31 output respectively corresponding to time-domain signal from 24 outputs of space-time code device.Each of S/P transducer 39-1 and 39-2 from two signals of S/P transducer 31 output a corresponding string and be converted to wave beam space-time code code element with the number of expanding section, be used for sending.Its wave beam space-time code code element of S/P transducer 39-1 output gives two-dimensional expansion device 32-1 to 32-m respectively, and its wave beam space-time code code element of S/P transducer 39-2 output gives two-dimensional expansion device 32-2 to 32-2m respectively.Two-dimensional expansion device 32-1,2 to 32-m, the wave beam space-time code code element of 2m reception and distribution string and conversion is given expanding section as shown in Figure 3.Two-dimensional expansion device 32-1,2 to 32-m, and 2m uses the Walsh sign indicating number at each expanding section, with the two-dimensional expansion of carrying out in time and frequency domain or direction, and spread signal is outputed to multiplexer 40-1 to 40-m.
As shown in Figure 3, use the quantity (SF of the OFDM code element in the time domain Time) and frequency domain in the quantity (SF of subcarrier Freq) definition is as the two-dimensional expansion section of extended area.Time domain expander 32-1,2 to 32-m, and 2m uses that extended code dispensing controller 26 distributed has spreading factor (SF TimeX SF Freq) extended code of (that is the time domain spreading factor x frequency domain expansion factor).At first, two-dimensional expansion device 32-1,2 to 32-m, 2m carries out the time domain expansion at first subcarrier, carries out the time domain expansion at the carrier wave adjacent with first subcarrier then.Expand by repeating time domain by this way, two-dimensional expansion device 32-1,2 to 32-m, 2m carries out two-dimensional expansion in time domain and frequency domain.
Multiplexer 40-1 to 40-m in same expanding section from two-dimensional expansion device 32-1,2 to 32-m, two code elements (in time domain) of exporting in each of 2m are carried out multiplexing, and multiplexing code element is outputed to other user's multiplexers 36.For example, multiplexer 40-1 is multiplexing carrying out from two code elements (time domain) of two-dimensional expansion device 32-1 and 32-2 output in same expanding section, and multiplexing code element is outputed to other user's multiplexers 36.
Other subscriber signal multiplexers 36 are received in the wave beam space-time code transmit symbol of time domain and frequency domain two-dimensional expansion, and multiplexing a plurality of users' code element, and multiplexing data are exported to pilot signal multiplexer 34.
The pilot signal of pilot signal multiplexer 34 temporal extension (or time domain expansion) wave beam, pilot signal and with the multiplexing growth data of other user's data carry out multiplexing, and this in addition multiplexing data output to IFFT+GI 35.
IFFT+GI 35 is converted to time-domain signal to the data that receive by invert fast fourier transformation (IFFT).IFFT+GI 35 also is added to protection interval (GI) in the signal, carries out the up-conversion of carrier frequency, then the signal of frequency conversion is outputed to transmitting antenna array 20.
Transmitting antenna array 20 comprises a plurality of respectively corresponding to the antenna (in this embodiment be n antenna) of antenna branch 25-1 to 25-n.A plurality of the transmitting that transmitting antenna array 20 emissions each IFFT+GI 35 from antenna branch 25-1 to 25-n receives.
The single wave beam that uses as user is identical with one of a plurality of wave beams of another user's use, or one of a plurality of wave beams of using of one of a plurality of wave beams of using of user and another user are when identical, and extended code dispensing controller 26 provides the extended code of 0 partial correlation for these beam allocation in the time domain expansion.In addition, when a plurality of users use same wave beam to the time, extended code dispensing controller 26 provides the extended code of 0 partial correlation to distribute to corresponding wave beam in the time domain expansion.The extended code that 26 outputs of extended code dispensing controller are distributed is given two-dimensional expansion device 32-1, and 2 to 32-m, each of 2m.
As how distributing as shown in Fig. 4 of extended code, use wave beam to (#1, user #2) and use wave beam to (#3 in the explanation extended code, user #4) belongs to group A, and use wave beam to (#2, user #3) and use wave beam are to (#4, user #1) belong to group B.If suitably narrow to the expansion of the path angle of each terminal, then distribute to not interference between the right signal of different beams in same group by wave beam from the base station.In addition, when idle bit is decoded at that time, do not disturb each other at a plurality of users' of same wave beam centering signal, because these users use same wave beam right.But, (see equation 8 to 9) as mentioned above, belonging to not between the signal of different user on the same group has distracter.
In order to prevent to disturb, in the following manner extended code is distributed to user's (or wave beam to).The extended code of the leaf that produces respectively corresponding to the group node from a plurality of nodes that have identical time domain spreading factor (seeing " X " among Fig. 4) the Walsh shown in Fig. 4 expansion code tree is distributed to the user that belongs to same group (or wave beam to).But, corresponding to from the different group nodes the Walsh shown in Fig. 4 expansion code tree (X compares with the time domain spreading factor, be root or more near the node of root) produce respectively not on the same group leaf not on the same group extended code distribute to the user who belongs to not on the same group.
In the example shown in Fig. 4,32 extended code 0-15 (seeing " A " among Fig. 4) are assigned to and belong to group A (promptly, use wave beam to (#1, user #2) and use wave beam are to (#3, user #4)) user, wherein 32 extended code 0-15 are from having a plurality of nodes X of same time domain spreading factor (seeing " X " Fig. 4) 1To X 8In a group node (X 1, X 2, X 3And X 4) leaf that produces respectively.32 extended code 16-31 (seeing " B " among Fig. 4) are assigned to and belong to group B (promptly, use wave beam to (#2, user #3) and use wave beam are to (#4, user #1)) user, wherein 32 extended code 16-31 are from having a plurality of nodes X of same time domain spreading factor (seeing " X " Fig. 4) 1To X 8In a group node (X 5, X 6, X 7And X 8) leaf that produces respectively.
In brief, extended code dispensing controller 26 is according to following regular allocation extended code.
1) from different branches produce not on the same group the time domain extended code be assigned to different groups.
2) extended code of the different branches generation from the time domain spreading factor is assigned to same user as two extended codes.
3) if the extended code that the different branches from the time domain spreading factor produce has residue, then remaining extended code is assigned to uses other right users of same wave beam.
4) same extended code (wherein without limits) can be assigned to the right user of use different beams in same group.
Figure 12 is how explanation is carrying out wave beam space-time emission diversity method according to the base station 2 in the wave beam space-time transmit diversity systems of second embodiment.
As shown in Figure 10, if first to the 4th wave beam #1 is launched to #4 by transmitting antenna array 20 in base station 2, travelling carriage 1 passes through the wave beam #1 of antenna 10 reception emissions to #4, and by switch 11 wave beams that receive from antenna 10 is offered channel estimator 12-1 to 12-4.Channel estimator 12-1 to 12-4 to the signal despreading that receives to estimate channel response, then estimated channel response is outputed to power calculator 13-1 to 13-4.
Power calculator 13-1 is to the power of 13-4 calculating channel response, and the power addition of calculating on all subcarriers, to estimate the power separately from these wave beams.Adder 14-1 is to each power of channel response separately addition corresponding to two adjacent beams of each adder of 14-n, and these two channel response power with output to maximum wave beam to power and detector 15.
Four wave beams that maximum wave beam receives from four adder 14-1 to 14-n more respectively power and detector 15 to power and, with determine four wave beams to power and maximum.Maximum wave beam to power and detector 15 corresponding to determined maximum wave beam to power and wave beam index and this wave beam are estimated to output to power difference comparator 16 to the power separately of a plurality of wave beams (being two in this embodiment) of index representative.By this way, from a plurality of wave beams (being four in this embodiment), select to provide the maximum channel responding power and two adjacent beams.
Difference between the power of channel response separately of two selected wave beams of power difference comparator 16 detections, and output is given list/multi-beam selector 17 about the information whether this difference is lower than predetermined threshold.Just, power difference comparator 16 received beams are estimated the power separately of a plurality of wave beams of index representative index and this wave beam, difference and predetermined threshold between relatively institute's received power is estimated output to list/multi-beam selector 17 to this comparative result then.
If the power difference that power difference comparator 16 is calculated is lower than predetermined threshold, then list/multi-beam selector 17 is selected these two wave beams, if and this power difference is equal to or greater than predetermined threshold, then only select one of two wave beams to use as single wave beam, a selected wave beam is bigger than another power.Just, list/multi-beam selector 17 receives the comparative result of this wave beam to the difference between the power estimation of a plurality of wave beams of index representative, from a plurality of wave beams, select single or multiple wave beams according to comparative result, and exporting to antenna 10 corresponding to the beam index of a selected wave beam or a plurality of wave beams by switch 11.Antenna 10 sends to base station 2 to this beam index.
With reference to Figure 11, base station 2 execution error correction codings are launched the order of the modulation signal point mapping randomization data emission of data by 23 pairs of interleavers, and use the signal space-time code of orthogonal space-time encoder matrix to exporting from interleaver 23 of above-mentioned two row, two row.Next, base station 2 is given the signal allocation of space-time code from a wave beam or a plurality of wave beam of the selected beam index representative of travelling carriage 1 reception.
As shown in Figure 12, the beam rider guidance vector 1201 and 1202 by two wave beams flows [s at two space-time codes respectively 1,-s 2 *] and [s 2, s 1 *] go up and carry out wave beam formation, wherein the user is between these two wave beams.If b 1And b 2The beam index of two wave beams of expression can be used for s with equation 10 expression so 1And-s 2 *The beam rider guidance vector, can express with equation 11 and be used for s 2, and s 1 *The beam rider guidance vector.Just, the beam rider guidance vector 1201 and 1202 by equation 10 and 11 flows [s at two respectively 1,-s 2 *] and [s 2, s 1 *] go up and carry out wave beam formation, multiplexing and encoding flows after this.
W b 1 = [ W b 1 1 , W b 1 2 , . . . , W b 1 N a ] T - - - ( 10 )
W b 2 = [ W b 2 1 , W b 2 2 , . . . , W b 2 N a ] T - - - ( 11 )
The signal of equation 12 expression is exported second constantly at the signal of first output constantly and equation 13 expression.
V 1 = S 1 W b 1 + S 2 W b 2 = [ V 1 1 , V 1 2 , . . . , V 1 N a ] T - - - ( 12 )
V 1 = - S 2 * W b 1 + S 1 * W b 2 = [ V 2 1 V 2 2 , . . . , V 2 N a ] T - - - ( 13 )
The element of output signal V is respectively corresponding to antenna branch.
Constantly obtain output signal V first by each antenna branch 1 IA, constantly obtain output signal V by each antenna branch second 2 IAThese output signals V 1 IAAnd V 2 IAGone here and there and changed, used extended code c respectively at antenna branch #iA then 1And c 2Expansion is re-used at same expanding section then.
Suppose wave beam be assigned to as at the wave beam of Fig. 7 to group A shown in the classification chart and B.For example, if being the extended code of time domain spreading factor twice, spreading factor is assigned to a pilot signal, so, the extended code of the leaf that produces respectively corresponding to the group node in a plurality of nodes that have identical time domain spreading factor (seeing " Z " among Fig. 7) in the Walsh shown in Fig. 7 expansion code tree is just distributed to the wave beam that uses on the same group mutually.
Therefore be assigned to pilot signal because spreading factor is the extended code of two times of above time domain spreading factors, 16 extended codes 1 ' to 4 ' just are assigned to the pilot signal the signal of the user in group A and B.
At each expanding section, the Walsh sign indicating number is used to carry out the two-dimensional expansion at time domain and frequency domain.Use according to wave beam shown in Figure 7 extended code using herein.
These code elements and other users' of obtaining in the same manner signal multiplexing.Each subcarrier in the two-dimensional expansion section, use is expanded pilot signals with a plurality of extended codes of the extended code quadrature of subscriber signal, and pilot signal and subscriber signal are multiplexing then.
The frame signal (see figure 8) of Chan Shenging is converted into time-domain signal by fast Flourier (IFFT) inverse transformation by this way.Add protection (GI) at interval to this time-domain signal, this time-domain signal is up-converted to carrier frequency, launches (beam pattern of seeing fixed beam shown in Figure 9) simultaneously from all antennas of transmitting antenna array 20 then.
Travelling carriage 1 (or recipient) is converted to the reception sub-carrier signal to the signal that receives by fast fourier transform.Use the sub-carrier signal time despreading of extended code to receiving on each subcarrier, wherein the pilot signal of wave beam is assigned to described subcarrier.From despread signal, remove the pilot modulated item, from wave beam, to obtain channel estimating.
This user's extended code time despreading received signal is distributed in use, to suppress to cause the interference signals item.Then, this signal is decoded by space-time, and makes up the signal of decoding at frequency domain.Despread signal is deinterleaved, then by error correction decoding, with the bit sequence that obtains regenerating.
From top description obviously as can be seen, the wave beam space-time transmit diversity systems according to second embodiment of the invention has the following advantages.In launch scenario, wherein adopt in the OFDM-CDM system of two-dimensional expansion and use emission multi-beam array in conjunction with space-time code, emission side carries out extended code and distributes, so as to make the recipient can by the time domain despreading the time idle bit suppress to cause interference signals when decoded.This can prevent to disturb, and reduces because the interference of frequency selectivity between code.
In addition, owing to use a plurality of extended codes to a plurality of space-time code code element expansions in the time domain, these code elements are re-used at same expanding section then, so the time change that Doppler frequency causes influences very little.Correspondingly, can provide emitting performance and systematic function.
In addition, in the wave beam space-time transmit diversity systems according to second embodiment, the spatial domain signal of exporting from the space-time code device is assigned to beam space.Therefore, if the user suitably lays respectively in a plurality of wave beams, then all multiplexing signals not all arrive each travelling carriage, and have only the signal of sharing the user of wave beam with travelling carriage to arrive this travelling carriage.Therefore, may reduce arrival subscriber signal quantity and reduce interference between code.
Existing systems is used a plurality of extended areas to the time-domain signal from the output of space-time code device.But, will distribute to a plurality of extended codes and at same extended area multiplexed signals from the time-domain signal of space-time code device output according to the system of second embodiment, thus the repellence that becomes when having increased to channel.
More specifically, can reduce because the interference between the code that selectivity of channel frequency causes, and become interference between the code that causes when reducing channel according to the wave beam space-time emission system of second embodiment, and the reduction of the decoding characteristics of idle bit when preventing.
In addition, in the space-time transmit diversity systems according to second embodiment, orthogonal pilot signals is assigned to wave beam, or pilot signal is re-used after with the orthogonal spreading code expansion.Therefore, the recipient can estimate the channel response from each wave beam.By the power of calculating channel estimation response, can know the residing beam area of travelling carriage.
In addition, because the base station is given two adjacent beams or a single wave beam space-time code signal allocation of encoding with the orthogonal space-time encoder matrix of two row, two row, so the recipient calculate from the power of the channel estimating of adjacent beams and, with detect representative provide maximum wave beam to power and the wave beam of two adjacent beams to index.
In addition, if big, just can not effectively utilize one that has lower-wattage in two wave beams from the difference between the channel response power of two selected wave beams.Therefore, only have the single wave beam that the selected conduct of more powerful another wave beam will be used, and beam selection information sends to the base station in up link.This just makes the base station can discern effective wave beam that each travelling carriage is removed in distribution.
But in existing extended code allocative decision, when idle bit was decoded at that time, shared common beam also used the right subscriber signal of different beams to disturb.In order to address this problem, consider that different branches produce from the extended code generation tree extended code has zero partial correlation according to the spreading factor of different branches, distributes the extended code of the different branches generation from the extended code generation tree in the above described manner.This extended code is distributed makes receiver suppress the interference user signal by the time domain despreading, thereby does not produce interference when idle bit was not decoded at that time.
In addition, the code of the two-dimensional expansion factor told from the different branches of time domain spreading factor can be distributed to same user as two extended codes.This enables by time domain despreading separation signal, thereby realizes space-time code.
In addition, in extended code is distributed, the different branches from the time domain spreading factor tell not on the same group extended code preferentially be assigned to and use the right a plurality of users of same beam.This makes receiver can suppress other users' signal by the time domain despreading.Therefore, can prevent interference between frequency domain Assemble Duration extended code.
All comprise computer system in each of transmitter and receiver in travelling carriage and base station 1 and 2 therein.Be used to carry out said system operation, the program of selecting such as space-time code, space-time decoding and beam index is stored in the computer readable recording medium storing program for performing with the form of program.Computer can be by reading in program stored executable operations in this medium.
For example, for each processing unit or the element in the transmitter and receiver of operating or be implemented in above-mentioned travelling carriage and base station 1 and 2, in CPU (CPU) from such as the main storage of ROM or the RAM fetch program of transmitter and receiver in each, with information processing and the calculating of carrying out this program.
Computer readable recording medium storing program for performing comprises disk, magneto optical disk, CD-ROM, DVD-ROM, semiconductor memory or the like.Such program also can be sent to computer by order wire, thereby can make computer carry out the program that is transmitted.
Although for illustration purpose has been described the preferred embodiments of the present invention, those skilled in the art should recognize to have various modifications, add and delete, and do not break away from the disclosed scope and spirit of the present invention of claim.

Claims (21)

1, a kind of transmit diversity systems comprises:
Transmitter, being used for the signal space-time code that will launch is the space-time code signal, carry out the time domain expansion of this space-time code signal and frequency domain expansion producing spread signal, and behind the beam space of this spread signal being distributed to a plurality of wave beams according to the feedback information that receives from receiver, launch this spread signal; And
The assignment of code device, according to described feedback information, if, be distributed in the extended code that has 0 partial correlation in the time domain expansion if one of a plurality of wave beams that the single wave beam that user uses is included in a plurality of wave beams that another user uses or user uses are used by another user.
2, according to the system of claim 1, wherein also to distribute the partial correlation that has in the time domain expansion in addition be that 0 extended code is given the right user of a plurality of use same beam to this assignment of code device.
3, a kind of transmitter, being used for the signal space-time code that will launch is the space-time code signal, carry out the time domain expansion of this space-time code signal and frequency domain expansion with the generation spread signal, and this spread signal of emission behind the beam space of this spread signal being distributed to a plurality of wave beams, described transmitter comprises:
The assignment of code device, if if one of a plurality of wave beams that the single wave beam that user uses is included in a plurality of wave beams that another user uses or user uses are used by another user, be distributed in then that to have partial correlation in the time domain expansion be 0 extended code.
4, according to the transmitter of claim 3, wherein this assignment of code device also is distributed in the time domain expansion in addition to have partial correlation is that 0 extended code is given the right user of a plurality of use same beam.
5, a kind of extended code allocating method in transmit diversity systems, this system comprises transmitter, being used for the signal space-time code that will launch is the space-time code signal, carry out the time domain expansion of this space-time code signal and frequency domain expansion with the generation spread signal, and this spread signal of emission behind the beam space of this spread signal being distributed to a plurality of wave beams according to the feedback information that receives from receiver said method comprising the steps of:
According to described feedback information, if, be distributed in the extended code that has 0 partial correlation in the time domain expansion if one of a plurality of wave beams that the single wave beam that user uses is included in a plurality of wave beams that another user uses or user uses are used by another user.
6, a kind of extended code allocating method in transmit diversity systems, this system comprises transmitter, being used for the signal space-time code that will launch is the space-time code signal, carry out the time domain expansion of this space-time code signal and frequency domain expansion with the generation spread signal, and this spread signal of emission behind the beam space of this spread signal being distributed to a plurality of wave beams according to the feedback information that receives from receiver said method comprising the steps of:
According to described feedback information, distribute extended code to give the right user of a plurality of use same beam with 0 partial correlation of expanding in time domain.
7, a kind of transmit diversity systems comprises:
Transmitter, being used for the signal space-time code that will launch is the space-time code signal, carry out the time domain expansion of this space-time code signal and frequency domain expansion producing spread signal, and behind the beam space of this spread signal being distributed to a plurality of wave beams, launch this spread signal;
The beam allocation device is used for distributing the space-time code signal to give a plurality of wave beams of these a plurality of wave beams in the spatial domain; And
The extended code distributor is used for distributing the space-time code signal to a plurality of extended codes in same extended area in time domain.
8, according to the system of claim 7, wherein this beam allocation device selects wave beams right from a plurality of wave beam centerings of these a plurality of wave beams of receiver reception, selected wave beam to maximum power with the channel estimating separately that is included in two right wave beams of described wave beam and, if and the difference between the power of the channel estimating separately of two wave beams of selected wave beam centering is greater than predetermined value, then this beam selection device from these two wave beams, select one and distribute the space-time code signal in this spatial domain give in these two wave beams selected this.
9, according to the system of claim 7, if if wherein one of a plurality of wave beams that the single wave beam that uses of user is included in a plurality of wave beams that another user uses or user uses are used by another user, then this extended code distributor is distributed in the extended code that has 0 partial correlation in the same extended area.
10, system according to Claim 8, wherein the wave beam in the following manner this beam allocation device selected of this extended code distributor is to being categorized as wave beam to group, this mode makes the wave beam that does not disturb each other to being classified as same wave beam to group, and wave beam interfering with each other is to being classified as different wave beams to group, and the extended code distributor distributes the extended code of the two-dimensional expansion factor to give these different wave beams to group, and described extended code is that the different branches from the time domain extension layer of expansion code tree branch away.
11, system according to Claim 8, described one in two wave beams selecting to the beam allocation device of this extended code distributor extended code of distributing the two-dimensional expansion factor wherein, described extended code is that the different branches from the time domain extension layer of expansion code tree branch away.
12, a kind of emission diversity method in transmit diversity systems, this transmit diversity systems comprises transmitter, being used for the signal space-time code that will launch is the space-time code signal, carry out the time domain expansion of this space-time code signal and frequency domain expansion with the generation spread signal, and this spread signal of emission behind the beam space of this spread signal being distributed to a plurality of wave beams said method comprising the steps of:
A) in the spatial domain, distribute the space-time code signal to give a plurality of wave beams of these a plurality of wave beams; And
B) in time domain, distribute the space-time code signal to a plurality of extended codes in same extended area.
13, according to the method for claim 12, if wherein corresponding to the difference between the power of the channel estimating separately of two right wave beams of the wave beam of a plurality of wave beam centerings selections of this a plurality of wave beams that receive from receiver greater than predetermined value, then from be included in two right wave beams of selected wave beam, select the space-time code signal in and this spatial domain be assigned in these two wave beams selected this, wherein selected wave beam to the maximum power of channel estimating separately with two wave beams that are included in described wave beam centering and.
14, according to the method for claim 12, if, be distributed in the extended code that has 0 partial correlation in the identical extended area so if wherein one of a plurality of wave beams that the single wave beam that uses of user is included in a plurality of wave beams that another user uses or user uses are used by another user.
15, according to the method for claim 13, if, be distributed in the extended code that has 0 partial correlation in the identical extended area so if wherein one of a plurality of wave beams that the single wave beam that uses of user is included in a plurality of wave beams that another user uses or user uses are used by another user.
16, according to the method for claim 13, wherein in the following manner have maximum power and wave beam to be categorized as wave beam to the group, this mode makes the wave beam that does not disturb each other to being classified as same wave beam to group, and wave beam interfering with each other is to being classified as different wave beams to group, and the extended code of distributing the two-dimensional expansion factor gives different wave beams to group, and described extended code is that the different branches from the time domain extension layer of expansion code tree branch away.
17, according to the method for claim 14, wherein in the following manner have maximum power and wave beam to be categorized as wave beam to the group, this mode makes the wave beam that does not disturb each other to being classified as same wave beam to group, and wave beam interfering with each other is to being classified as different wave beams to group, and the extended code of distributing the two-dimensional expansion factor gives different wave beams to group, and described extended code is that the different branches from the time domain extension layer of expansion code tree branch away.
18, according to the method for claim 15, wherein in the following manner have maximum power and wave beam to be categorized as wave beam to the group, this mode makes the wave beam that does not disturb each other to being classified as same wave beam to group, and wave beam interfering with each other is to being classified as different wave beams to group, and the extended code of distributing the two-dimensional expansion factor gives different wave beams to group, and described extended code is that the different branches from the time domain extension layer of expansion code tree branch away.
19, according to the method for claim 13, the extended code of wherein distributing the two-dimensional expansion factor is to described one in selected two wave beams of beam allocation device, and described extended code is that the different branches from the time domain extension layer of expansion code tree branch away.
20, according to the method for claim 14, the extended code of wherein distributing the two-dimensional expansion factor is to described in selected two wave beams of beam allocation device one, and described extended code is that the different branches from the time domain extension layer of expansion code tree separate.
21, according to the method for claim 15, the extended code of wherein distributing the two-dimensional expansion factor is to described in selected two wave beams of beam allocation device one, and described extended code is that the different branches from the time domain extension layer of expansion code tree separate.
CNA2008100049991A 2003-04-25 2004-04-26 Transmit diversity system and method, transmitter and extended code allocating method Pending CN101242210A (en)

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