CN101958865A - Method for generating demodulating reference signal and device thereof - Google Patents
Method for generating demodulating reference signal and device thereof Download PDFInfo
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Abstract
The invention discloses a demodulating reference signal design method and a device thereof, including a demodulating reference signal design pattern, a demodulating reference signal scrambling scheme, an allocation scheme of demodulating reference signal in single cell and an allocation scheme of the demodulating reference signal among multiple cells. The invention also provides a channel estimation method corresponding to the allocation scheme. The invention is not only applicable to single cell, but also to implementation of demodulating reference signal among multiple cells.
Description
Technical field
The present invention relates to a kind of demodulated reference signal that in cell mobile communication systems, uses, particularly a kind of coherent demodulation reference signal generation method of in multicarrier system, using and corresponding channel estimation methods.
Background technology
Multicarrier system is OFDM (OFDM) system for example, is the main flow multi-transceiver technology in the third generation (3G) wireless communication system afterwards.In ofdm system, data are modulated on the subcarrier of OFDM frequency domain with the form of modulation symbol usually, are transformed into the time-domain sampling point by fast adverse Fourier transform (IFFT) then, form transmitting of base band.After signal was launched by radio frequency (RF), electromagnetic wave arrived receiver through behind the wireless channel of eating dishes without rice or wine.The target of receiver is exactly how correctly to carry out demodulation to sending signal.
Though differential ference spiral and blind Detecting do not need extra expense, but the demodulation mode of main flow is to be still by insert known data (pilot reference signal (RS)) on the time frequency unit at OFDM place to realize the estimation to wireless channel at present, thereby realizes effective demodulation.Therefore, the demodulation that how can realize modulation symbol with the expense of minimum is the key of RS design.From the angle of system, higher pilot density can improve channel estimated accuracy, and channel estimating must be accurate more, and the performance loss of separating timing is just few more, and therefore the rate of delivering a letter that can support is just high more, otherwise then low more.But another aspect, higher pilot density can increase the expense of system simultaneously, increase expense and mean the minimizing of the available resources number that system is total, thereby can reduce the capacity of system.
Therefore how effectively first key point of RS design is exactly good its expense of balance, so that the capacity of system reaches maximization.
After having determined the expense of reference signal, another key point is exactly the concrete pattern of pilot tone.The shape of pilot tone pattern, position etc. can have influence on performance for estimating channel to a certain extent.At present, the new generation broadband wireless communication system, as with third generation partnership projects standardized (3GPP) Long Term Evolution (LTE) system, and be representative with Institute of Electrical and Electric Engineers (IEEE) standardized 802.16 (802.16d/e/m) system, the mode that interleaves frequency pilot sign on time frequency unit that all is to use realizes.Its difference is that the different system sample rate is different, and the different system time frequency unit is in different size, the pilot tone pattern the time, interval on the frequency domain is also different.
Sight from the communication system of single subdistrict, (LTE is IEEE802.16) because pilot tone quadrature on time frequency unit, therefore under acceptable expense in above system, the demodulation performance of link reference signal from point to points, they all satisfy performance requirement.Yet commercial on a large scale at present wireless communication system all is a honeycomb.The characteristics of honeycomb are the channelings on can the implementation space.As the global system for mobile communications (GSM) of the second generation, just can realize multifrequency point channelings such as 4 looks, 7 looks by the isolation on the space length.The cellular network of second generation frequency division multiplexing is enough in the epoch based on speech.Yet being the epoch of main demand with digital multimedia, under the more and more rarer situation of frequency spectrum resource, simple multifrequency point channeling can not satisfy the demand of market to communication service far away.Multiple sectors at same networking frequently, or even the requirement of whole network identical networking is more and more higher.
The evaluating system model that the wireless communication system scheme (4G or 3.9G) that present IMT-A is collecting adopts at least is 19 websites, and each website has 3 sub-districts (57 sub-districts altogether), and there are a plurality of antennas or a plurality of different transmission data Layer in each sub-district.In the system of IMT-A, all sub-districts often send different user data and signal on same running time-frequency resource.Under many sub-districts, many antennas condition, system entails can be subjected to strong jamming like this.Under strongly disturbing multi-cell system model, the design of the reference signal of simple time-frequency quadrature will no longer be optimum.If the scheme of time-frequency quadrature that will single subdistrict expands to many sub-districts, a kind of natural selection is that the reference signal with neighbor cell staggers mutually, then chiseling out with the data of RS on same running time-frequency resource little adjacent sub-district.In the LTE system, 3 sub-districts under the same site, when each sub-district was 4 transmit antennas, the expense of bringing was 42.86% because the running time-frequency resource of RS and data symbol staggers, expense can be bigger in the time will increasing the sub-district again.Therefore the method that chisels out of frequency displacement position on time, overhead will be unacceptable, the user that almost few of resource can be given in each sub-district uses.
Therefore, under the condition of many sub-districts, how under controlled overhead, realize in the network in the different districts multiplexing between reference signal and different antennae, and guarantee enough channel estimating quality, become the significant challenge in the cellular radio Communication system of new generation.
Summary of the invention
Main purpose of the present invention is to provide a kind of reference signal method of generationing that can effectively support to be used under many sub-districts the code division multiplexing (CDM) that coherent demodulation uses, to solve the communicating requirement of the identical networking under the many sub-districts of support, the many antennas spectral efficient.
According to first aspect, reference signal generation method of the present invention comprises: according to application scenarios, frequency pilot sign is placed in the multicarrier time-frequency two-dimensional structure appropriate location, to form at least four kinds with reference to one of signal pattern.
According to second aspect, the generation method of reference signal of the present invention may further comprise the steps:
In number of pilot symbols and character position unit, select number of pilot symbols and the position of frequency pilot sign in subframe;
In frequency pilot sign frequency domain interval counting unit, select frequency pilot sign frequency domain interval number;
In frequency pilot sign subcarrier spacing unit, select the subcarrier spacing of frequency pilot sign;
Input length is nN
RBSequence as frequency pilot sign; And
Pilot tone pattern map unit is mapped to the pilot tone pattern according to the subcarrier spacing of selected number of pilot symbols and position, frequency pilot sign frequency domain interval number and the frequency pilot sign of frequency pilot sign in subframe with described frequency pilot sign.
Wherein said length is nN
RBSequence can form by following steps;
It is nN that sequence generator generates length
RBSequence sets;
The sequence selection device is selected a sequence from the sequence sets that described sequence generator generates;
Phase rotation device carries out the frequency domain linear phase shift to selected sequence; And
The sequence scrambler carries out the frequency domain scrambling with dephased sequence, thereby forms the scramble sequence as frequency pilot sign.
Wherein, described subframe is the base unit of signal transmission, and each subframe comprises 2 isometric time slots, and has following structure:
Each time slot is to be M by time length
SymSymbolic number and frequency domain is long is nN
RBThe rectangle time frequency unit formed of subcarrier, comprise M altogether
SymNN
RBIndividual subcarrier;
NN
RBThe resource block size of specific user on frequency domain, N are wherein given in the expression primary distribution
RBIt is the minimum length that the frequency domain data Resource Block takies.
Wherein, described pilot tone pattern can be: length is nN
RBFrequency pilot sign be placed on continuously in each described time slot on the optional sign position by same way as.
Wherein, described pilot tone pattern can be: length is nN
RBFrequency pilot sign be placed on discontinuously on each time slot by same way as, wherein said length is nN
RBFrequency pilot sign interleave placement on the first-class subcarrier spacing of frequency domain ground, be placed in time mark space.
Wherein, described pilot tone pattern can be: two length are nN
RBFrequency pilot sign be placed on respectively continuously on the character position of former and later two time slot adjacency of subframe; Having one or more on the perhaps whole subframe is nN two two length of being placed continuously on the character position
RBFrequency pilot sign.
Wherein, described pilot tone pattern can be: two length are nN
RBFrequency pilot sign be placed on respectively continuously on the character position of former and later two time slot adjacency of subframe, and the subcarrier spacing of frequency pilot sign is the little several times of data subcarrier; Perhaps, having one or more on the whole subframe is nN two two length of being placed continuously on the character position
RBFrequency pilot sign, and the subcarrier spacing of described frequency pilot sign is the little several times of data subcarrier.
Wherein, described phase rotation device by selected sequence is rotated the angle is
Rotation realize described frequency domain linear phase shift; And
Described sequence scrambler obtains described scramble sequence as frequency pilot sign by multiply by the rotatable sequence of described phase rotation device output with a scramble sequence.
Wherein, distributing different length to different websites in the network is nN
RBSequence, comprise following allocation step;
When the length of reference signal is enough, give the different cyclic shifts of the same website same sequence of different sub-district (comprising different antennae or different layers in the sub-district) distribution down;
When the length of reference signal is not enough, gives the different cyclic shifts of the same sequence of the first distribution in same website different sub-district (comprising different antennae or different layers) down the sub-district in, and then distribute different sequences and cyclic shift thereof;
The identical scramble sequence of identical time-frequency resource allocating in the network, the scramble sequence that different time-frequency resource allocating are different;
Identical sequence can be distributed in the sub-district of (as 4 times radius of society) separated by a distance.
According to the third aspect, the present invention also provides a kind of reference signal of utilizing said method to generate to carry out channel estimation methods under many sub-districts, may further comprise the steps:
Utilize Sampling for Wide-Band Signal point memory cell to obtain sampled point signal from antenna;
Utilize lock unit to finish the Time and Frequency Synchronization of described sampled point signal and received signal;
Utilization goes to remove CP the sampled point of CP (Cyclic Prefix) unit after synchronously;
Utilize the FFT unit that time-domain sampling is put signal transformation and become subcarrier in frequency domain;
The reference of taking out corresponding frequency domain position from the character position at reference signal RS place with reference to the reference signal unit on the RS symbol is got in utilization;
Utilization is gone to disturb the unit and remove described scrambler sequence from the RS signal that receives;
Utilize the RS signal transformation after the IDFT unit will go to disturb to arrive time domain;
Utilizing time-domain channel estimating unit to do time domain channel through the time-domain signal behind the IDFT unit estimates;
Utilize the DFT unit that the impulse response that time domain estimates is transformed to frequency domain;
Utilize the frequency domain filtering unit that domain channel response is done filtering at frequency domain;
Utilize time domain direction channel interpolating unit that frequency domain response is done further filtering and interpolation is carried out in the position of no reference signal, obtain the response of all subcarriers on the whole subframe, and then realize channel estimating.
The present invention not only is suitable for single subdistrict, more is adapted to the realization of the demodulated reference signal under a plurality of sub-districts.
On the other hand, utilize channel estimation methods of the present invention, can do further filtering and interpolation is carried out in the position of no reference signal, obtain the frequency domain response on all subcarriers of whole subframe frequency domain response.Then the data at the non-pilot tone place that takes out are carried out equilibrium, obtain the data after the demodulation, finish the process of whole channel estimation and equalization.
The present invention is described in detail below in conjunction with accompanying drawing.
Description of drawings
Fig. 1 is applicable to a kind of structure of time slot and subframe structure based on time frequency unit of the present invention;
Fig. 2 a is the schematic diagram of continuous a kind of reference signal of placing on frequency domain;
Fig. 2 b is the schematic diagram that interleaves a kind of reference signal of placement on frequency domain;
A kind of reference signal subcarrier spacing that Fig. 2 c places for continuous adjacent on frequency domain equals data subcarrier schematic diagram at interval;
A kind of reference signal subcarrier spacing that Fig. 2 d places for continuous adjacent on frequency domain equals the data subcarrier schematic diagram of half at interval;
Fig. 3 a is the distribution method of shorter reference signal under a kind of many sub-districts;
Fig. 3 b is the distribution method of short reference signal under a kind of many sub-districts;
Fig. 3 c is the distribution method of longer reference signal under a kind of many sub-districts;
Fig. 4 a is the pilot frequency design mapping device figure that can be used for realizing pilot tone pattern shown in Fig. 2 a to Fig. 2 d;
Fig. 4 b is the multi-district pilots pattern Mapping installation drawing that can be used for realizing pilot tone pattern shown in Fig. 2 a to Fig. 2 d;
Fig. 5 is the device for carrying out said that a kind of many sub-districts lower channel is estimated.
Embodiment
The present invention adapts to above-mentioned the problems of the prior art by generating a kind of reference signal (or demodulated reference signal).In the following description, term: reference signal, demodulated reference signal, pilot signal have identical notion.
Fig. 1 has shown a kind of signal basic transfer unit that is suitable for reference signal of the present invention, is a kind of time slot and subframe structure of Versatile two-dimension time frequency unit.Each time slot (slot) takies isometric M in time
SymIndividual symbol takies nN on frequency domain
RBIndividual subcarrier.RB is that (length is N
RB) be the base unit of system's Resources allocation on frequency domain direction, slot is the base unit of system's Resources allocation on the time domain direction.
Basic skills of the present invention is according to application scenarios, frequency pilot sign to be placed on the multicarrier time-frequency two-dimensional structure appropriate location, thereby to form four kinds shown in Fig. 2 a to Fig. 2 d with reference to one of signal pattern (that is the subframe that, has the pilot tone pattern).
Fig. 4 a has shown a kind ofly can generate four kinds shown in Fig. 2 a to Fig. 2 d with reference to any pilot tone pattern mapping device of signal pattern, utilizes this device to generate reference signal method and may further comprise the steps:
In number of pilot symbols and character position unit 406, select number of pilot symbols and the position of frequency pilot sign in subframe;
In frequency pilot sign frequency domain interval counting unit 407, select frequency pilot sign frequency domain interval number;
In frequency pilot sign subcarrier spacing unit 408, select the subcarrier spacing of frequency pilot sign;
Input length is nN
RBSequence as frequency pilot sign; And
Pilot tone pattern map unit 409 is mapped to the pilot tone pattern according to the subcarrier spacing of selected number of pilot symbols and position, frequency pilot sign frequency domain interval number and the frequency pilot sign of frequency pilot sign in subframe with described frequency pilot sign.
Pilot tone pattern map unit 409 can be to carry out the processor of mapping program, and the parameter of the relevant number of pilot symbols that it is imported according to unit 406, unit 407 and unit 408, the position in subframe, frequency domain interval number, subcarrier spacing is carried out mapping.Just, frequency pilot sign is placed on the relevant position of the frequency domain (that is, subcarrier) of subframe and time domain (being the symbol in the timely crack of time slot), thereby forms the pilot tone pattern according to these parameters.This pilot tone pattern and communication data are placed on respectively on the different time domain and frequency domain of subframe.
Fig. 4 b has shown a kind of multi-district pilots pattern Mapping device that can be used for realizing pilot tone pattern shown in Fig. 2 a to Fig. 2 d, and it is nN that the difference of it and Fig. 4 a shown device only has been to increase the length that adapts to multi-cell multi-antenna sequence allocation needs
RBControl, the alternative pack of sequence (being frequency pilot sign or sequence).
Shown in Fig. 4 b, length is nN
RBSequence can form by following steps;
It is nN that sequence generator 402 generates length
RBSequence sets;
404 pairs of selected sequences of phase rotation device are carried out the frequency domain linear phase shift; And
With reference to Fig. 1, described subframe is the base unit of signal transmission, and its each subframe comprises 2 isometric time slots, and has following structure:
Each time slot is to be M by time length
SymSymbolic number and frequency domain is long is nN
RBThe rectangle time frequency unit formed of subcarrier, comprise M altogether
SymNN
RBIndividual subcarrier;
NN
RBThe resource block size of specific user on frequency domain, N are wherein given in the expression primary distribution
RBIt is the minimum length that the frequency domain data Resource Block takies.
Referring to Fig. 2 a, described pilot tone pattern can be: length is nN
RBFrequency pilot sign be placed on continuously in each described time slot on the optional sign position by same way as.
Referring to Fig. 2 b, described pilot tone pattern can be: length is nN
RBFrequency pilot sign be placed on discontinuously on each time slot by same way as, wherein said length is nN
RBFrequency pilot sign interleave placement on the first-class subcarrier spacing of frequency domain ground, be placed in time mark space.
Referring to Fig. 2 c, described pilot tone pattern can be: two length are nN
RBFrequency pilot sign be placed on respectively continuously on the character position of former and later two time slot adjacency of subframe; Perhaps, having one or more on the whole subframe is nN two two length of being placed continuously on the character position
RBFrequency pilot sign.
Referring to Fig. 2 d, described pilot tone pattern can be: two length are nN
RBFrequency pilot sign be placed on respectively continuously on the character position of former and later two time slot adjacency of subframe, and the subcarrier spacing of frequency pilot sign is the little several times of data subcarrier; As selection, can have one or more on the whole subframe is nN two two length of being placed continuously on the character position
RBFrequency pilot sign, and the subcarrier spacing of described frequency pilot sign is the little several times of data subcarrier.
For different websites in the network, can distribute different length is nN
RBSequence, phase rotation device 404 can be realized not homotactic distribution by the sequence of selecting is carried out the frequency domain linear phase shift.Sequence allocating method is as follows:
When the length of reference signal is enough, give the different cyclic shifts of the same website same sequence of different sub-district (comprising different antennae or different layers in the sub-district) distribution down;
When the length of reference signal is not enough, gives the different cyclic shifts of the same sequence of the first distribution in same website different sub-district (comprising different antennae or different layers) down the sub-district in, and then distribute different sequences and cyclic shift thereof;
The identical scramble sequence of identical time-frequency resource allocating in the network, the scramble sequence that different time-frequency resource allocating are different;
Identical sequence can be distributed in the sub-district of (as 4 times radius of society) separated by a distance.
In addition, the reference signal that the present invention also provides a kind of utilization to generate is as stated above carried out the channel estimation methods under many sub-districts, and wherein Fig. 5 has shown a kind of device that can realize this method.
The concrete steps that realize channel estimating are described below in conjunction with Fig. 5.
Utilize Sampling for Wide-Band Signal point memory cell 500 to obtain sampled point signal from antenna;
Utilize lock unit 501 to finish the Time and Frequency Synchronization of described sampled point signal and received signal;
Utilization goes to remove CP the sampled point of CP (Cyclic Prefix) unit 502 after synchronously;
Utilize FFT unit 503 that time-domain sampling is put signal transformation and become subcarrier in frequency domain;
The reference of taking out corresponding frequency domain position from the character position at reference signal RS place with reference to the reference signal unit on the RS symbol 504 is got in utilization;
Utilization is gone to disturb unit 505 and remove described scrambler sequence from the RS signal that receives;
Utilize the RS signal transformation after IDFT unit 506 will go to disturb to arrive time domain;
Utilizing time-domain channel estimating unit 507 to do time domain channel through the time-domain signal behind the IDFT unit estimates;
Utilize DFT unit 508 that the impulse response that time domain estimates is transformed to frequency domain;
Utilize frequency domain filtering unit 509 that domain channel response is done filtering at frequency domain;
Utilize 510 pairs of frequency domain responses of time domain direction channel interpolating unit to do further filtering and interpolation is carried out in the position of no reference signal, obtain the response of all subcarriers on the whole subframe, and then realize channel estimating.
System reference with the Long Term Evolution plan (LTE) of 3GPP is that example further specifies implementation process of the present invention below.
In the LTE system, each subframe has 2 slot, and each slot is that the time span that 7 symbols and each slot occupy is 0.5ms, and the length of each RB is 12 subcarriers, subcarrier spacing is 15kHz, and system is the integral multiple of 12 subcarriers for the bandwidth of user's primary distribution.19 websites that the structure of many sub-districts is then given by senior international mobile telecommunication (IMT-A), the structure of 57 sub-districts are the topological structure of many sub-districts.
Fig. 2 a is the pilot tone pattern example of a kind of RS, and sub-carrier number is 1 N on the frequency domain that provides among the figure
RB, here just as a kind of illustrated example, can a plurality of RB (nN of primary distribution in actual allocated
RB).The characteristics of this distribution are, the time domain direction is on each slot, and RS is on the middle symbol of slot, and the RS signal is placed on subcarrier continuously on the frequency domain.A subframe goes up adjacent 2 slot, and upward the RS signal can be identical, also can be different.Such pilot tone pattern is applicable to RB moderate length on the frequency domain, and user's speed of a motor vehicle is higher speed and following situation thereof.
Fig. 2 b is the pilot tone pattern example of second kind of RS, and the time-frequency structure among the figure and Fig. 2 a are similar, different is RS signal the time, interval on the frequency is different.In Fig. 2, what provide is on each slot, and uniformly-spaced respectively to place a reference signal on the symbol from the slot both sides, reference signal is equally spaced placement on frequency domain, between be spaced apart 1.In the scheme of reality, interval d
fCan be 1, also can be 2,3 values that wait other.On the symbol at each RS place, the sequence length of RS correspondence be the length of Resource Block divided by space-number, that is: nN
RB/ d
fSame, at each RS symbol place, reference signal can be identical, also can be different.Further, the RS symbolic number on time slot can be 2, also can be other value.A kind of common following the example of to the RS symbolic number equals the space-number length d of RS on frequency domain
fSuch pilot tone pattern is applicable to that RB length is suitable longer on the frequency domain, and user's speed of a motor vehicle is a situation at a high speed.
Fig. 2 c is the pilot tone pattern of the third RS, and the RS of the third type places on frequency domain continuously, in time placed adjacent on two middle symbols of subframe.This RS pilot tone pattern also first kind similar, it is not both: the sequence length of first type pilot tone pattern is nN
RB, and the length of the third pilot tone pattern RS is 2nN
RBIn addition, from the position, the third is be placed on subframe middle, and first kind is be placed on each slot middle.In addition, the third pilot tone pattern is a complete continuous sequence, and just first half and the latter half with sequence has been placed on respectively on two adjacent symbols.Such pilot tone pattern is applicable to the networking condition on a large scale than low speed.At this moment, can support with single RB to be the distribution of the data resource piece of unit effectively.
Fig. 2 d is the pilot tone pattern of the 4th RS, and is similar on time location with the third type.Be the subcarrier spacing of the third pilot frequency design and the subcarrier spacing identical (as all being 15kHz) of data division, whole RS signal is that a complete sequence is placed on respectively on two adjacent symbols of front and back.And the 4th kind subcarrier spacing is at interval half of data subcarrier, takies the OFDM symbol (be a RS sub-carrier this moment) of two data subcarriers altogether.The length of the Cyclic Prefix (CP) of the big symbol of RS this moment also is the twice of general data subcarrier CP length.Such RS structure, the work under the networking frequently of the multiple sectors at same in being suitable for equally under the low speed condition can be supported complicated many cell environments that big time delay is expanded effectively.
After various dissimilar pilot tone pattern among Fig. 2 has been arranged, the sequence of CDM can be placed on the symbol at RS part place.For up emission,, therefore in up emission, distribute the sequence of CDM can not bring the problem of high PAPR because user (UE) usually only takies the bandwidth of the part of system.And in descending base station, then system might send the signal of full bandwidth simultaneously, when the length of RS more in short-term, the shared situation of identical reference sequences then might appear, the transmitting and the problem of high PAPR can occur of base station this moment.The method that the present invention further discloses a kind of frequency domain scrambling solves this problem.Selected after the pilot frequency mode of specific RS, the living journey step that is placed on the CDM RS scrambled signals on the pilot sub-carrier is as follows:
Fig. 3 is at 19 websites, the distribution method of reference signal under 57 sub-districts.Fig. 3 (a) is the distribution diagram of short running time-frequency resource position of reference signal, and this moment, hypothesis had 36 different sequences (comprising different cyclic shifts).Such as, suppose a RB, be 12 sequence as length, to suppose to have 12 different sequences this moment, each sequence can obtain 3 different cyclically shifted sequences (N with cyclic shift
Zcz=4), can regard as this moment altogether 36 different sequences.Then can carry out the distribution of many sub-districts by the mode of Fig. 3 (a).4 streams (or four different antennas) are arranged in each sub-district of hypothesis among Fig. 3 (a).Each letter and footmark thereof are (as A
1) four different sequences in having represented 36.36 different sequences can realize the distribution of whole network by the structure shown in Fig. 3 (a).When the sub-district number in the network greater than 57 the time, can nestedly expand by the structure among the figure.
Fig. 3 b and Fig. 3 a are similar, just comprise different cyclic shifts this moment, suppose to have 48 different sequences.Same, when the sub-district number in the network greater than 57 the time, can nestedly expand by the structure among Fig. 3 b.Also be applicable to the less situation of RB number that Resource Block takies this moment on frequency domain.
Fig. 3 c is suitable for having used pilot frequency design 3 or 4, perhaps the resource block length on the frequency domain long (as 4 RB, length be 48 and above length) time situation.This moment, system can provide different reference sequences more than 19 at least, and 19 websites can distribute different sequences, 3 sub-districts each website under can distribute not homotactic cyclic shift (during as 4 antennas in each sub-district or 4 layers, distribution N
Zcz=4), the different districts under the same website just in time can be accomplished quadrature at this moment, and the different districts under the different websites can be accomplished low correlation.
Fig. 4 b is a kind of multi-district pilots pattern mapping device figure.400 Cell Identity CIs (ID) unit, sequence is selected according to its ID number and the antenna port below it or the numbering 401 of floor in the sub-district.It is nN that sequence generator 402 generates length
RBSequence sets.Sequence sets is to have good low, zero correlation characteristic, simultaneously with sequence transformation after time domain, the time domain sequences that obtains still has good low, zero correlation characteristic, as GCL sequence, Chu sequence, Milewski sequence, Luke sequence etc.Sequence selection is carried out in the output of sequence generator 402 in 403 under 401 control.In the 403 sequence selection devices, the mode of sequence selection is the cyclic shift that the different antennae (layer) in the different districts under the same site is selected same sequence as much as possible, and the different antennae in the sub-district under the different sites (layer) is selected other sequence in the sequence sets.The corresponding same sequence of the cyclic shift of sequence is done the size of linear phase shift at frequency domain, and size is N
ZczIntegral multiple.403 is after each antenna (layer) is chosen sequence, sequence to be done the linear phase shift of frequency domain in 404 phase rotation devices.405 with the scrambling on frequency domain of dephased sequence.The method of linear phase shift and scrambling is seen the explanation of Fig. 2 correspondence.In 406, select the number and the position of frequency pilot sign in subframe of frequency pilot sign then, in 407, select frequency pilot sign frequency domain interval number, space-number can be 0,1,2 etc., the subcarrier spacing of selected frequency pilot sign under 406～408 control, is mapped to corresponding pilot tone pattern with the sequence after 405 scramblings in 409 in 408.And export the pilot tone pattern that designs, and then in 410, the son of data map to non-pilot tone carried on the position, data and pilot tone lump together and be mapped to a complete subframe in 411.
Fig. 5 is a kind of many sub-districts disclosed by the invention lower channel estimation unit.Receiver earlier obtains being input to sampling number certificate the base band Sampling for Wide-Band Signal point memory 500 from current antenna opening, so realizes Time and Frequency Synchronization in the lock unit 501.Data are synchronously removed CP in going to CP unit 502.To remove data behind the CP in 503 FFT converter unit with the data conversion of the sampled point that receives in frequency domain.Take out subcarrier nN corresponding on the RS symbol in Unit 504
RBThen the RS symbol that takes out is realized going to disturb in Unit 505, go the method for disturbing opposite, promptly multiply each other corresponding, with the scrambler of removal scrambling with local scrambled signals of storing and the RS signal partly that receives with the process of scrambling.RS signal after will going then to disturb is nN
RBThe IDFT unit 506 that passes through of point transforms to time domain.Do minimum variance (LS) in the channel estimating unit 507 of time domain and estimate, obtain the channel impulse response on the subband at time domain RS place.Time domain channel shock response is obtained the channel response of frequency domain again by DFT unit 508, and then in 509 frequency domain filtering unit, realize frequency domain filtering.The method of frequency domain filtering is least mean-square error (MMSE) or linear minimum mean-squared error criterion (LMMSE) filtering.After the filtering again on the time domain direction frequency domain response to other symbol place carry out interpolation.
The above is preferred embodiment of the present invention only, is not to be used to limit protection scope of the present invention.
Claims (11)
1. a reference signal generation method comprises according to application scenarios, frequency pilot sign is placed on the appropriate location of multicarrier time-frequency two-dimensional structure, to form at least four kinds with reference to one of signal pattern.
2. the generation method of a reference signal may further comprise the steps:
In number of pilot symbols and character position unit (406), select number of pilot symbols and the position of frequency pilot sign in subframe;
In frequency pilot sign frequency domain interval counting unit (407), select frequency pilot sign frequency domain interval number;
In frequency pilot sign subcarrier spacing unit (408), select the subcarrier spacing of frequency pilot sign;
Input length is nN
RBSequence as frequency pilot sign; And
Pilot tone pattern map unit (409) is mapped to the pilot tone pattern according to the subcarrier spacing of selected number of pilot symbols and position, frequency pilot sign frequency domain interval number and the frequency pilot sign of frequency pilot sign in subframe with described frequency pilot sign.
3. method according to claim 2, wherein said length are nN
RBSequence can form by following steps;
It is nN that sequence generator (402) generates length
RBSequence sets;
Sequence selection device (403) is selected a sequence from the sequence sets that described sequence generator (402) generates;
Phase rotation device (404) carries out the frequency domain linear phase shift to selected sequence; And
Sequence scrambler (405) carries out the frequency domain scrambling with dephased sequence, thereby forms the scramble sequence as frequency pilot sign.
4. according to claim 2 or 3 described methods, wherein said subframe is the base unit of signal transmission, and each subframe comprises 2 isometric time slots, and has following structure:
Each time slot is to be M by time length
SymSymbolic number and frequency domain is long is nN
RBThe rectangle time frequency unit formed of subcarrier, comprise M altogether
SymNN
RBIndividual subcarrier;
NN
RBThe resource block size of specific user on frequency domain, N are wherein given in the expression primary distribution
RBIt is the minimum length that the frequency domain data Resource Block takies.
5. method according to claim 4, wherein said pilot tone pattern is:
Length is nN
RBFrequency pilot sign be placed on continuously in each described time slot on the optional sign position by same way as.
6. method according to claim 4, wherein said pilot tone pattern is:
Length is nN
RBFrequency pilot sign be placed on discontinuously on each time slot by same way as, wherein said length is nN
RBFrequency pilot sign interleave placement on the first-class subcarrier spacing of frequency domain ground, in time by mark space be placed.
7. method according to claim 4, wherein said pilot tone pattern is:
Two length are nN
RBFrequency pilot sign be placed on respectively continuously on the character position of former and later two time slot adjacency of subframe; Perhaps
Having one or more on the whole described subframe is nN two two length of being placed continuously on the character position
RBFrequency pilot sign.
8. method according to claim 4, wherein said pilot tone pattern is:
Two length are nN
RBFrequency pilot sign be placed on respectively continuously on the character position of former and later two time slot adjacency of subframe, and the subcarrier spacing of described frequency pilot sign is the little several times of data subcarrier; Perhaps
Having one or more on the described whole subframe is nN two two length of being placed continuously on the character position
RBFrequency pilot sign, and the subcarrier spacing of described frequency pilot sign is the little several times of data subcarrier.
9. method according to claim 3, wherein:
Described phase rotation device (404) by selected sequence is rotated the angle is
Rotation realize described frequency domain linear phase shift; And
Described sequence scrambler (405) obtains described scramble sequence as frequency pilot sign by multiply by the rotatable sequence of described phase rotation device (404) output with a scramble sequence.
10. method according to claim 3, wherein distributing different length to different websites in the network is nN
RBSequence, comprise following allocation step;
When the length of reference signal is enough, give the different cyclic shifts of the same website same sequence of different sub-district (comprising different antennae or different layers in the sub-district) distribution down;
When the length of reference signal is not enough, gives the different cyclic shifts of the same sequence of the first distribution in same website different sub-district (comprising different antennae or different layers) down the sub-district in, and then distribute different sequences and cyclic shift thereof;
The identical scramble sequence of identical time-frequency resource allocating in the network, the scramble sequence that different time-frequency resource allocating are different;
Identical sequence can be distributed in the sub-district of (as 4 times radius of society) separated by a distance.
11. a reference signal of utilizing the described method of claim 1 to generate is carried out the channel estimation methods under many sub-districts, may further comprise the steps:
Utilize Sampling for Wide-Band Signal point memory cell (500) to obtain sampled point signal from antenna;
Utilize lock unit (501) to finish the Time and Frequency Synchronization of described sampled point signal and received signal;
Utilization goes to remove CP the sampled point of CP (Cyclic Prefix) unit (502) after synchronously;
Utilize FFT unit (503) that time-domain sampling is put signal transformation and become subcarrier in frequency domain;
The reference of taking out corresponding frequency domain position from the character position at reference signal RS place with reference to the reference signal unit on the RS symbol (504) is got in utilization;
Utilization is gone to disturb unit (505) and remove described scrambler sequence from the RS signal that receives;
Utilize the RS signal transformation after IDFT unit (506) will go to disturb to arrive time domain;
Utilizing time-domain channel estimating unit (507) to do time domain channel through the time-domain signal behind the IDFT unit estimates;
Utilize DFT unit (508) that the impulse response that time domain estimates is transformed to frequency domain;
Utilize frequency domain filtering unit (509) that domain channel response is done filtering at frequency domain;
Utilize time domain channel interpolating unit (510) that frequency domain response is done further filtering and interpolation is carried out in the position of no reference signal, obtain the response of all subcarriers on the whole subframe, and then realize channel estimating.
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| CN102724758A (en) * | 2011-03-25 | 2012-10-10 | 北京新岸线无线技术有限公司 | Method and system for adjusting demodulation pilot frequency in wireless communication system |
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| CN102299769B (en) * | 2011-09-01 | 2014-06-25 | 电信科学技术研究院 | Downlink control information transmission method and device |
| CN102299769A (en) * | 2011-09-01 | 2011-12-28 | 电信科学技术研究院 | A downlink control information transmission method and device |
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| CN105763490A (en) * | 2015-12-30 | 2016-07-13 | 广东顺德中山大学卡内基梅隆大学国际联合研究院 | Improved in-band noise reduction DFT channel estimation algorithm |
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| CN109937552A (en) * | 2016-11-10 | 2019-06-25 | 高通股份有限公司 | For supporting the sequence of the system of hybrid digital scheme to generate |
| CN109937552B (en) * | 2016-11-10 | 2021-12-03 | 高通股份有限公司 | Sequence generation method and apparatus for system supporting hybrid digital scheme |
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| US12015569B2 (en) | 2016-11-10 | 2024-06-18 | Qualcomm Incorporated | Sequence generation for systems supporting mixed numerologies |
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| CN108282309B (en) * | 2017-01-06 | 2021-09-07 | 华为技术有限公司 | Reference signal transmission method and device |
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