CN1751489B - Pilot transmission schemes for wireless multi-carrier communication systems - Google Patents
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Abstract
Pilot transmission schemes suitable for use in wireless multi-carrier (e.g., OFDM) communication systems. These pilot transmission schemes may utilize frequency, time, or both frequency and time orthogonality to achieve orthogonality among the pilots transmitted by multiple base stations on the downlink. Frequency orthogonality is achieved by transmitting pilots on disjoint sets of subbands. Timeorthogonality is achieved by transmitting pilots using different orthogonal codes (e.g., Walsh codes). The pilots may also be scrambled with different scrambling codes, which are used to randomize pilot interference and to enable identification of the transmitters of these pilots. Pilot interference cancellation may be performed to improve performance since subbands used for data transmission by one transmitter may also be used for pilot transmission by another transmitter. Pilot interference is estimated and then subtracted from received symbols to obtain pilot-canceled symbols having improved quality.
Description
The application requires in interim U. S. application sequence number 60/438,601 priority, the latter is entitled as " PilotTransmission Schemes for Wireless Multi-Carrier CommunicationSystems ", be filed on January 7th, 2003, be transferred to assignee of the present invention, and be incorporated herein by reference fully at this.
Technical field
The present invention relates generally to communication, relate in particular to the pilot transmission schemes that is used for wireless multi-carrier communication system.
Background technology
Multi-carrier communications systems uses a plurality of carrier waves to be used for transfer of data to single endpoint.These a plurality of carrier waves can be used for as OFDM (OFDM) or some other multi-carrier modulation technologies.OFDM is divided into the total system bandwidth a plurality of (N) orthogonal subbands effectively, and they also become tone, frequency section and frequency subchannels.In OFDM, each subband is associated with the corresponding carrier wave of modulating data thereon.
In wireless communication system, the data that send are managed (for example encode and modulate) everywhere at transmitter, and upconvert to radio frequency (RF) carrier signal to generate the RF modulated signal.The RF modulated signal is sent out on wireless channel then and can arrives receiver by a plurality of propagation paths.The characteristic of propagation path usually since a plurality of factors along with the time changes, described factor is such as for example decay, multipath and external disturbance.Therefore, the RF modulated signal of transmission may experience different channels condition (for example different decay and multipath effect), and may be associated in different complex gain and signal to noise ratio (snr) in time.
In wireless communication system, pilot tone often sends to receiver (for example terminal) from transmitter (for example base station) and realizes a plurality of functions to help receiver.Pilot tone generally generates and handles in known manner based on known code element.Pilot tone can be used for that channel estimating, timing and frequency are obtained by receiver, the coherence data demodulation, receive signal strength measurement etc.
In the pilot transmission schemes design of multi-carrier communications systems, face multiple challenge.A kind of consideration is because pilot transmission is represented expense system in, and expectation minimizes pilot transmission as far as possible and the while still provides the performance of expection.Another consideration is the pilot tone that the send mode of pilot tone will make intrasystem reception function detect and interior each transmitter of distinguishing system sends.And pilot transmission schemes need solve the additional dimension of a plurality of carrier waves foundation of multicarrier system.
Therefore in this area a kind of needs to pilot transmission schemes in the multi-carrier communications systems are arranged.
Summary of the invention
Provide the pilot transmission schemes that is suitable for use in wireless multi-carrier communication system (for example ofdm system) at this.These pilot transmission schemes can utilize frequency orthogonal, time quadrature or both are with the orthogonality between the pilot tone that obtains to be sent by a plurality of base stations on the down link.Frequency orthogonal can obtain by send pilot tone from different base stations on disjoint sets of subbands.Time quadrature can obtain by using different orthogonal sign indicating number (for example Walsh sign indicating number) to send pilot tone.Pilot tone can also be carried out scrambler with different scramblers, and described scrambler is used for the randomization Pilot Interference and makes the transmitter identity of these pilot tones of energy identification.
Pilot transmission schemes described here has made things convenient for channel estimating and detection of pilot effectively.The pilot frequency intensity that these schemes allow intrasystem terminal can obtain base station in high-quality broad-band channel estimation and the system is estimated.These estimations can be used to realize coherence data demodulation, soft handover and direct-cut operation, and are as described below.
The estimation and the cancellation techniques of Pilot Interference are also provided at this.Can realize that Pilot Interference offsets improving performance, because the subband that is used for data or pilot transmission by a transmitter can also be used for pilot transmission by another transmitter (i.e. " interference " transmitter).The estimation of Pilot Interference can realize in the following manner: obtain the estimation of channel to interference source; The same way as that realizes with jamming transmitter generates pilot tone; And the pilot tone that generates be multiply by channel estimating.Pilot Interference is deducted with the pilot tone behind the acquisition quality improvement from the code element that receives then offsets the back code element.
Various aspects of the present invention and embodiment are in following detailed description.
Feature of the present invention, characteristic and advantage become clearer from the detailed description below in conjunction with accompanying drawing, reference character identical among the figure identifies homologue, wherein:
Brief description of the drawings
Fig. 1 illustrates the wireless multiple access multi-carrier communications systems;
Fig. 2 A illustrates the OFDM sub band structure;
Fig. 2 B illustrates T non-intersect sets of subbands based on the OFDM sub band structure shown in Fig. 2;
Fig. 3 A and 3B are depicted as the 9-sector 3-cell cluster and the corresponding exemplary sub-band of 21-sector 7-cell cluster that obtain frequency orthogonal and distribute;
The example allocation that Fig. 4 A and 4B illustrate orthogonal code respectively obtains time quadrature with the 3-sector 1-cell cluster that each sector is had an antenna and two antennas;
Fig. 4 C and 4D illustrate the subband and the orthogonal code example allocation of 9-sector 3-cell cluster and 21-sector 7-cell cluster respectively, to obtain frequency and time quadrature;
Fig. 5 illustrates the example system layout, and wherein different scramblers is assigned to each 7-cell cluster;
Fig. 6 A and 6B illustrate respectively to the lock-out pulse pilot transmission schemes and synchronously the continuous pilot transmission plan from the pilot transmission of a plurality of sectors;
Fig. 7 illustrates the block diagram of base station and terminal;
Fig. 8 illustrates the block diagram of base station internal modulator;
Fig. 9 A and 9B illustrate the block diagram of two embodiment of demodulator in the terminal; And
Figure 10 illustrates the block diagram of the Pilot Interference canceller in the demodulator.
Embodiment
" example " speech is used herein to finger " as example, example or explanation ".Anyly not necessarily to be understood that to be better than other embodiment or design in this embodiment or design that is described as " example ".
Fig. 1 illustrates wireless multiple access multi-carrier communications systems 100, and described system supports a plurality of users, and can realize pilot transmission schemes described here.System 100 comprises a plurality of base stations 110, and they support the communication of a plurality of terminals 120.The base station is the fixed station that is used for terminal communication, and can also be called access point, Node B or some other terms.
Illustrate as Fig. 1, each terminal 120 can be dispersed in the system, and each terminal can be fixing (promptly static) or move.Terminal can also be called as mobile radio station, distant station, subscriber equipment (UE), Wireless Telecom Equipment, access terminal or some other terms.Each terminal can be communicated by letter at any given time with a plurality of base stations on down link and/or up link.Down link (being forward link) refers to the communication link from the base station to the terminal, and up link (being reverse link) refers to the communication link from terminal to base station.In Fig. 1, terminal 120a receives pilot tone, signaling and possible user's particular data transmission from base station 110a to 110g to 120o.
System controller (not illustrating in Fig. 1) generally is coupled to base station 110, and can be designed to realize a plurality of functions, realize coordinating and control for the base station of being coupled to it such as (1), (2) are with data route between these base stations, and the terminal of these base station services is inserted and controlled in (3).
System 100 can be the wireless system of cellular system or some other types.System 100 can also be designed to realize any standard and design, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA) etc.The CDMA standard comprises IS-95, cdma2000, IS-856, W-CDMA and TS-CDMA, and the TDMA standard comprises GSM.These standards are that the crowd knows in this area.
Intrasystem each base station 110 provides the covering of specific geographical area 102.The overlay area of each base station can be defined as the zone that terminal for example can obtain specified service class (GoS).The size of the overlay area of each base station and shape generally depend on various factors, such as landform, barrier etc.For simplicity, the overlay area of each base station is represented with desirable hexagon usually.Base station and/or its overlay area generally are commonly called " sub-district ", depend on the context that this term uses.
In the General System arrangement, for the increase capacity, the overlay area of each base station can be divided into a plurality of sectors.If each sub-district is divided into three sectors, then each sector of the sub-district of sectorization represents that with 120 desirable degree wedge shapes it is 1/3 of sub-district usually.In actual arrangement, the overlay area of each base station has usually and is different from desirable hexagonal shape, and the shape of each sector usually is different from 120 desirable wedge shapes.And the sector of sectorized cells is generally overlapping in edge.Each sector can be served by corresponding base transceiver subsystem (BTS).For through the sub-district of sectorization, the base station of this sub-district generally includes all BTS that serve the sector of this sub-district." sector " term also be often used in refer to BTS with and/or its overlay area, this depends on the environment that this term uses.
For simplicity, below describe each sub-district of hypothesis and be divided into three sectors, and its BTS is positioned at the base station of this sub-district.This base station is positioned at the center of sub-district.And for simplicity, in the following description, " base station " speech generally is used for the fixedly fixed station of Serving cell and the fixed station of serving sector.
For cdma system, the pilot tone that each base station sends is being dispersed on the channel on the whole system bandwidth before the transmission on the wireless channel.In end, the pilot tone that each base station sends can be received with low signal-to-noise ratio (SNR).Yet the complementation that terminal realizes goes extended operation that processing gain is provided, and this has relied on much noise and disturbed condition recovers pilot tone down.For multicarrier system, generally can not realize handling as the Direct swquence spread spectrum that uses in the CDMA to pilot tone.Thereby must use other devices to send pilot tone from each base station, make it easily to be detected by intrasystem terminal.
Provide the pilot transmission schemes that is applicable to multi-carrier communications systems at this, such as illustrate in Fig. 1 that.As mentioned above, send the various functions of pilot tone, such as regularly and frequency is obtained, channel estimating, coherence data demodulation etc. to support that normal system operation may need.Can also provide a plurality of carrier waves by OFDM and some other multi-carrier modulation technologies.Pilot transmission schemes described here is applicable to down link well, also can be used for up link.
For clear, pilot transmission schemes is that the down link of ofdm system is described specially.This ofdm system has N orthogonal subbands.Each base station can send an OFDM code element, following description in each OFDM code element in period.
I. pilot transmission is constructed
| Structure | Describe |
| Frequency orthogonal | On different non-intersect sets of subbands, send pilot tone to obtain the frequency domain orthogonality of pilot transmission by different base station |
| Time quadrature | By different base station is that pilot tone uses different orthogonal sign indicating number (for example Walsh sign indicating number) to obtain the time domain orthogonal of pilot transmission |
| Scrambler | By different base station is that pilot tone uses different scrambling codes to be used for randomize pilot interference and base station identity sign |
Quadrature and disturb " sign indicating number " and also be called as " sequence " in the following description.Each that list in the form 1 is structured in following detailed description.The processing of base station and these structures of end is also in following description.
Various pilot transmission schemes can also be based on any one or any Combination Design of these structures.For example, pilot transmission schemes can use (1) frequency and time quadrature, (2) frequency orthogonal and scrambler, (3) frequency orthogonal, time quadrature and scrambler, or (4) some other combinations.
1. frequency orthogonal
Frequency orthogonal can be used to avoid a plurality of base stations to carry out the interference that pilot transmission causes simultaneously.For frequency orthogonal, pilot tone is sent in the different sub-band set by a plurality of base stations, and described sets of subbands is that " non-intersect " (non-intersect in following description) is to avoid interference.Frequency orthogonal performance accomplished in various ways, some is described below.
Fig. 2 A illustrates OFDM sub band structure 200, and this structure can be used for multicarrier system 100.There is total system bandwidth W MHz in system, and it is divided into N orthogonal subbands using OFDM.In general ofdm system, have only M to be used for pilot tone and transfer of data, wherein M＜N in N total subband.A remaining N-M subband is not used in pilot/data transmission, covers requirement and meet frequency spectrum as protection with the permission system.M available subband comprises subband F to F+M-1, and wherein F is an integer, and general selection makes M available subband concentrate on the center of operational frequency bands.
Fig. 2 A also illustrates the embodiment of M available subband of a division pilot transmission.In this embodiment, M available subband is divided into K group when beginning, and each group comprises T subband continuously.Generally, each can be integer greater than one for K, T and M, and KT≤M.T subband in each group is assigned to T set then, makes that i subband in each group is assigned to i set.
Fig. 2 B illustrates the T subband set that generates based on the division shown in Fig. 2 A and closes.K subband in each T set illustrates with dash box.For this embodiment, K subband in each set evenly distributes on the available subband of M, and the interior continuous intersubband of set by T intersubband every.The T subband set is closed and can be assigned to T sub-district or pilot transmission is carried out in T sector.Each sub-district or sector can only send pilot tone on the subband in the set of distributing to this cell/section.
As a specific example, multicarrier system can have 512 subbands, and they are assigned with the index with 1 to 512.In these 512 subbands, can also distribute 50 subbands for the pilot transmission in each sector.Therefore, these 512 subbands can also be used to form the set (being T=9 and K=50) of 9 50 subbands, as illustrating in the form 2.
These 9 subband set are closed and can be assigned to 9 different sectors then and carry out pilot transmission.
Generally, M available subband can be assigned to T set in every way, and this within the scope of the invention.T set can comprise the subband of identical or different quantity.And the subband in each set can be evenly or is distributed in unevenly on M the available subband.The T subband set is closed " non-intersect " mutually, to avoid interference.Sets of subbands is mutually disjointed mutually, makes each of M available subband be assigned to maximum set.Each set comprises that also the subband of sufficient amount is so that terminal can be described channel based on the pilot transmission on these subbands only.Generally, the set quantity of formation and the number of sub-bands (being the particular value of T and K) that is included in each set may depend on various factors, such as:
● the quantity of available subband in the system;
● the time delay expansion of system and coherence bandwidth, this largest interval of having determined continuous pilot intersubband in each set is to avoid mis-behave;
● obtain frequency orthogonal bunch size; And
● whether time quadrature also is used for pilot transmission.
The Cyclic Prefix of OFDM code element (as described below) can be defined as comprising C
pIndividual sampling, wherein C
pBased on the time delay expansion of system and, make Cyclic Prefix comprise the pith of all multipath energy through suitable selection.For fear of mis-behave, the selection of the number of sub-bands in each set (K) can be so that K 〉=C
p, and these subbands can be evenly distributed on the system operation bandwidth.In this case, the maximum number of the disjoint set that can form is N/C
pFor example, if N=256, and C
p=16, then can form nearly 16 subband set and close.Can also form number disjoint set still less, wherein each set comprises more than C
pSubclass.In this case, comprise that the sub band number that requires more than minimum can be so that pilot reception has higher signal quality, thereby channel estimating that can be improved and pilot frequency intensity are estimated.Perhaps, can form more disjoint set number, each set comprises and is less than C
pIndividual subband.In this case, comprise that being less than the minimum sub band number that requires may cause the characteristic of frequency selectivity of operational frequency bands insufficient, and the deterioration of some performance may take place.
For simplicity, each that describe below that hypothesis T subband set closes comprises K subband, and the interior subband of each set distributes equably and is spaced apart T subband (illustrating as Fig. 2 B), and KT=M.The set number that forms depend on the desired frequency orthogonality and bunch size, as described below.
Fig. 3 A illustrate the exemplary sub-band branch be equipped with obtain to have to 3 sub-districts bunch frequency orthogonal, wherein each sub-district comprises 3 sectors (being 9-sector 3-cell cluster).Each of 9 sectors in bunch is assigned with of closing with 9 subband set (can for example as forming in the form 2) with illustrating.The sets of subbands of distributing to each sector is represented by the digital reference adjacent to the arrow of Fig. 3 A.Each sector only sends its pilot tone on the subband in the set of its distribution then.9 sectors in bunch can send simultaneously its pilot tone on 9 non-intersect sets of subbands, and obtain the frequency domain orthogonality simultaneously and avoid interference.
Fig. 3 B illustrates the exemplary sub-band distribution and thinks bunch acquisition frequency orthogonal that has 7 sub-districts, and wherein each sub-district comprises 3 sectors (being 21-sector 7-cell cluster).Bunch in each of 21 sectors be assigned with one that closes with 21 subband set.21 sectors in bunch can simultaneously send its pilot tone simultaneously in 21 subband disjoint sets, and obtain the orthogonality in the frequency domain simultaneously and avoid interference.
Generally, bunch can be defined as comprising any amount of sub-district, and each sub-district can comprise any amount of sector.As example, bunch can be defined as comprising 1,2,3,7 or 19 sub-districts.Bunch size can depend on various factors, such as act as listed above.
Can also be for being that pilot tone and transfer of data use the system of a plurality of antennas to obtain frequency orthogonal at each place, sector, to obtain spatial dispersion and to improve reliability.For example, each sector can use space-time emission diversity (STTD) scheme or Almouti scheme from two antenna transmission data.The STTD scheme is in 3G TS25.211 and in interim U.S. Patent Application Serial Number 60/421, describe in 309, the latter is entitled as " MIMOWLAN system ", is filed on October 25th, 2002, be transferred to assignee of the present invention at this, and be hereby incorporated by.The Alamouti scheme is described in being entitled as " A Simple TransmitDiversity Technique for Wireless Communications " by S.M.Alamouti, and this article is published in IEEE JSAC, and Oct.1998 also is included as reference at this.For the system of the sector that has a plurality of antennas, each antenna can be assigned with different subset set.
2. time quadrature
Time quadrature can be realized by the pilot tone with each sub-district of different orthogonal sign indicating number " covering " or sector.In end, can " go to cover " and recover receiving signal by the same orthogonal code used with this cell/section from the pilot tone of each cell/section.Overwrite procedure is the given pilot tone that will send or data symbols all Q chip of multiply by (promptly having Q pilot/data code element set of given value) Q chip orthogonal sequence to obtain code element after Q the covering, and described code element is further processed and transmission subsequently.Go overwrite procedure be Q chip of the code element that the receives orthogonal sequence that multiply by (a) identical Q chip and (b) complex conjugate (or complex conjugate of Q pilot/data code element) of pilot tone or data symbols go to cover code element to obtain Q, they are then through adding up with the pilot tone that obtains to send or the estimation of data symbols.It is known covering and going to cover in this area, and in following description.Go to cover and remove or offset the pilot tone that sends by other cell/sections that use the different orthogonal sign indicating number for its pilot tone.Like this, can realize from the orthogonality between the pilot transmission of a plurality of cell/sections.
Validity by the pilot tone orthogonality that covers can depend on to have base station information regularly.Can obtain time quadrature for the sector of same cells, because operate simultaneously these sectors.Sub-district in each bunch or intrasystem all sub-districts can also be operated simultaneously to allow for the pilot tone acquisition time quadrature that these sub-districts send.
Time quadrature can obtain with all kinds orthogonal code, such as Walsh sign indicating number and orthogonal variable spreading factor (OVSF) sign indicating number.The length that is used for the orthogonal code that pilot tone covers depends on the quantity of the orthogonal code of requirement, this then depend on obtain time quadrature bunch size.For example, if to having the sub-district expected time orthogonality of 3 sectors, then need 3 orthogonal codes (being the sign indicating number in each sector), and each orthogonal code has 4 chip lengths.
| The Walsh sign indicating number | Value |
| W 1(n) | 1 1 1 1 |
| W 2(n) | 1 1 -1 -1 |
| W 3(n) | 1 -1 1 -1 |
| The Walsh sign indicating number | Value |
| W 4(n) | 1 -1 -1 1 |
Specific Walsh sign indicating number can be assigned to each sector or each antenna of given sub-district.The value of " 1 " of Walsh sign indicating number can indicate pilot frequency code element contrary (promptly
, and value " 1 " may be indicated no contrary.Identical Walsh sign indicating number can be applied to each subband that is used for pilot transmission.For each pilot subbands, four chips of Walsh sign indicating number are applied to four pilot frequency code elements that will send in four continuous OFDM code element periods.Therefore the length of Walsh sign indicating number be T
w=4T
Sym, T wherein
SymRepresent an OFDM code element period.If pilot transmission is longer than four OFDM code element periods, then identical Walsh sign indicating number can repeat repeatedly on demand.The Walsh sign indicating number also is called as Walsh sequence or Walsh code element, and T
wRepresent a Walsh code element period.
Fig. 4 A illustrates the example orthogonal code division and is equipped with the time quadrature (be 3-sector 1-cell cluster) of acquisition to the sub-district that has three sectors.Each of three sectors in the sub-district is assigned with different orthogonal codes.Three orthogonal codes distributing to 3 sectors are denoted as A, B and C.As representing in Fig. 4 A that the same sub-band set can be used by all three sectors in the sub-district.Be to obtain time domain orthogonal by using the different orthogonal sign indicating number then from the pilot transmission that these three sectors send.
Fig. 4 B illustrates the example orthogonal code division and is equipped with the time quadrature that acquisition has the sub-district of three sectors, and each sector uses two antennas to be used for pilot tone and transfer of data.Each of three sectors is assigned with two orthogonal codes sign indicating number of each antenna in the sub-district.Three pairs of orthogonal codes distributing to three sectors are marked as A/B, C/D and E/F.3 sector cells require six orthogonal codes altogether then, and each orthogonal code length is 8 chips.
The time quadrature characteristic may worsen owing to temporary transient variation the in the propagation path of base station and terminal room.Therefore, short orthogonal code is used in expectation, makes propagation path substantially constant duration of orthogonal code.
3. Zu He frequency and time quadrature
Can be pilot transmission frequency of utilization and time quadrature combination.In one embodiment, for bunch in a plurality of sub-districts obtain frequency orthogonal, be that a plurality of sectors in each sub-district obtain time quadratures.
Fig. 4 C is depicted as exemplary sub-band and the sign indicating number distribution that 9-sector 3 cell clusters obtain frequency and time quadrature.Each of three sub-districts in bunch is assigned with different sets of subbands to obtain the frequency orthogonal of these three minizones.Three sectors of each sub-district also are assigned with three different orthogonal codes to obtain three time quadratures between the sector.Each sector of each sub-district can be used the orthogonal code of its distribution to send its pilot tone then and only be sent on the subband in the set of distributing to its sub-district.Obtained in this bunch orthogonality then, and avoided interference from the pilot transmission of nine sectors.
Fig. 4 D is depicted as exemplary sub-band and the sign indicating number distribution that 21-sector 7-cell cluster obtains frequency and time quadrature.。Each of seven sub-districts in bunch is assigned with different sets of subbands.Three sectors of each sub-district also are assigned with different orthogonal codes.Each sector of each sub-district can be used the orthogonal code of its distribution to send its pilot tone and only be sent on the subband that distributes then.
Can also obtain frequency and time quadrature in some other modes, and this within the scope of the invention.For example, a plurality of sub-districts can be assigned with identical sets of subbands but different orthogonal codes.As another example, a plurality of sets of subbands can be assigned to a plurality of sectors of same cells, and bunch in different districts can be assigned with different orthogonal codes.
For the system of the sector that has a plurality of antennas, can be pilot transmission acquisition orthogonality in many ways from a plurality of antennas.In one embodiment, each sub-district is assigned with a subband set and closes, and each antenna in the sub-district is assigned with different orthogonal codes.If each sector comprises two antennas, then each sector can be assigned with the pair of orthogonal sign indicating number, illustrates as Fig. 4 B.In another embodiment, a plurality of sectors of sub-district are assigned with different orthogonal codes, and a plurality of antennas of each sector are assigned with different sets of subbands.Identical sets of subbands can be used for all sectors of same cells, and divides the antenna that is equipped with the same sub-band set to be assigned with different orthogonal codes.For example, for the 3-sector cell, each sector comprises two antennas, two subband set can be closed (for example gathering 1 and 2) and distribute to two antennas of each sub-district, and three sectors can be assigned with orthogonal code A, B and C.A sector of sub-district can be assigned with sets of subbands/orthogonal code 1-A and 2-A, and second sector can be assigned with 1-B and 2-B, and the 3rd sector can be assigned with 1-C and 2-C.
4. scrambler
Scrambler can be used for the randomization Pilot Interference and can carry out identify label to the base station.Different scramblers can be assigned to each sector, each sub-district or each bunch.Scrambler can be pseudo random number (PN) sequence or some other unique sequences.Scrambler can be applied to the pilot tone (for example before orthogonal code covers) in the frequency domain, as described below.Scrambler can also be applied in the time domain and (for example handle the back at OFDM), should be greater than the OFDM code check with the reserve frequency orthogonality in this situation scrambler speed.The complementary processing then realized to recover pilot tone by terminal.The scrambler of base station and end and go scrambler to handle following description.
Fig. 5 illustrates example system layout 500, and wherein different scramblers is assigned to each 7-cell cluster.Each bunch of cloth intra-office drawn with heavy line.Example bunch illustrates with seven shade sub-districts.For this embodiment, seven sub-districts in each bunch are assigned with different sets of subbands (being marked as 1 to 7), and three sectors in each sub-district are assigned with different orthogonal codes (being denoted as A, B and C).Can be identified as the sets of subbands that (1) distributes to the sub-district under the sector from the pilot transmission of each sector of cloth intra-office, (2) distribute to the orthogonal code of sector, and (3) distribute under the sector bunch scrambler.Other system layouts with different sub-band, orthogonal code and scrambler distribution can also be developed, and this within the scope of the present invention.
Illustrate as Fig. 5, the terminal in the given sector only can receive from other and be assigned with Pilot Interference with the sector of same sub-band set and same orthogonal code.For example, being marked as that terminal in the sector of 1-A only can receive from the layout internal labeling is the Pilot Interference of other sectors of 1-A.
Each scrambler S
i(n) be the sequence of unique code chip, wherein n is the chip index of sequence.In one embodiment, each scrambler chip is that form is
Complex values, s wherein
i(n) and
Each value can be 1 or-1.In other embodiments, scrambler can be defined in some other modes, and sign indicating number chip value or be real number or for plural.
Scrambler can be realized in many ways, depends on the characteristic of wireless channel.Generally, channel should be on the whole duration that each scrambler chip is employed substantially constant.The substantially invariable time interval of channel is called as coherence time and can represents with τ.The lengths table of orthogonal code is shown T
w, wherein for the 4 chip Walsh sequence T that illustrate in the form 3
w=4T
Sym
For the first scrambler scheme, if be far longer than the coherence time of channel orthogonal code length (be τ＞＞T
w), then scrambler can be employed on a plurality of orthogonal sequences.Particularly, can be applied to length be T to each scrambler chip
wAn orthogonal sequence on.Identical scrambler chip can be applied to each of K subband being used for pilot transmission.For the example Walsh sequence shown in the form 3, each scrambler chip is applied to four Walsh sign indicating number chips, and described chip is applied to four pilot frequency code elements sending in four continuous OFDM code element periods.
For the first scrambler scheme, in order to recover the pilot tone from particular sector, terminal can use orthogonal code and the scrambler of distributing to this sector to realize that it is that scrambler removes scrambler then that orthogonal code goes to cover.Terminal can also realize on all or part of scrambler sequence that coherent integration is to recover pilot tone and to distinguish " channel altogether " sector (promptly be assigned with same sub-band and gather but the sector of different orthogonal sign indicating number and/or scrambler).Coherent integration process refers to the process that a plurality of complex-valued symbols make up in the mode of considering its phase information.
For the second scrambler scheme, if the coherence time of channel is very short, makes terminal to go up and realize coherent integration that then each scrambler chip can be applied to a quadrature chip at single orthogonal sequence (or a Walsh code element).Identical or different scrambler chip can be used for K pilot subbands.For example, for the example 4 chip Walsh sequences that illustrate in the form 3, scrambler can define with 4-K length.The one K scrambler chip can be used for K pilot subbands of a Walsh sign indicating number chip, next K scrambler chip can be used for K pilot subbands of the 2nd Walsh sign indicating number chip, then K scrambler chip can be used for K pilot subbands of the 3rd Walsh sign indicating number chip, last K scrambler chip can be used for the 4th with K pilot subbands of Walsh sign indicating number chip at last.
For two kind of second scrambler scheme, identical scrambler sequence can be used by all base stations that will obtain time quadrature.Scrambler provides randomize pilot interference.Because identical scrambler sequence used by a plurality of base stations, each base station can be by the orthogonal code sign of its distribution, may be scrambler with and the sets of pilot subbands of distribution.
For the scrambler scheme, in order to recover pilot tone, terminal can be estimated for each pilot subbands derives pilot tone, and is as described below.Each the channel response that receiver then can (1) estimates to obtain a plurality of pilot tones and data subband based on the pilot tone of all K pilot subbands is estimated, and (2) obtain to receive pilot power and estimate that this is the quadratic sum of the pilot tone estimation amplitude of all K pilot subbands.The following detailed description of processing that terminal is carried out pilot tone.
II. pilot transmission schemes
Pilot tone can be sent on down link to make things convenient for pilot detection and channel estimating in every way by the base station.Pilot detection can be used to make things convenient for system synchronization (frequency and timing are obtained), direct-cut operation and soft handover.Channel estimating can be used to make things convenient for the coherence data demodulation.Form 4 is listed four example pilot transmission schemes of multi-carrier communications systems
For the pulse guide-frequency structure, each sector at the appointed time at interval or time slot (rather than continuously) send its pilot tone with impulse form.Each sector can send pilot tone and data in time division multiplexing (TDM) mode.For the continuous pilot structure, each sector sends its pilot tone continuously on its sets of pilot subbands that is assigned with.Each sector can send data not specifying on the available subband of the residue that is used for pilot transmission.
For synchro system, the timing of all sectors of all sub-districts is by synchronous (for example based on gps time or some other public timing resources) in the system.For asynchronous system, all sectors of each sub-district regularly can be by synchronously, but the timing of different districts is asynchronous in the system.
For the lock-out pulse pilot transmission schemes, sector and sub-district are synchronous in the system, and in identical assigned timeslot with its pilot tone of pulsing.For this scheme, all sectors send its pilot tone simultaneously, but pilot tone by disjoint set of using pilot subbands and/or orthogonal code orthogonalization.Data are not to be sent out during the pilot transmission period.Terminal can obtain higher-quality channel estimating for different sectors, because do not receive any interference from transfer of data.And, the channel estimating of given sector can be further interference by the pilot tone that sends by other sectors on the collection that offsets comfortable same pilot subband improve, wherein used interference cancellation technology as described below.
Fig. 6 A illustrates the transmission from the pilot tone of a plurality of sectors of lock-out pulse pilot transmission schemes.For this scheme, the sector is at the pulse T of specific duration
PilotSend its pilot tone on inherent disjoint sets of subbands, interpulse specified time interval is T
IntAs pointing out in Fig. 6 A that the timing of sector is synchronous, make pilot pulse roughly locate it in its transmission time.Each sector can send data in all available subbands in the time interval between pilot pulse.(for simplicity, frequency and time are not to draw in proportion in Fig. 6 A and Fig. 6 B).
For synchronous continuous pilot transmission plan, intrasystem sector and sub-district are synchronous, and its pilot tone of transmission on the sets of pilot subbands is being specified continuously in each sector.For this scheme, can further pass through to use the different orthogonal sign indicating number and quadrature from the pilot tone of different sectors.For each sector, data do not send on the sets of subbands of pilot transmission appointment.
Fig. 6 B illustrates in the synchronous continuous pilot transmission plan pilot transmission from a plurality of sectors.For this scheme, the sector sends its pilot tone continuously on disjoint sets of subbands.Each sector can not be to specify on other subbands that are used for pilot transmission to send data.Illustrate as Fig. 6 B, the timing of sector is synchronous.
For the asynchronous pulse pilot transmission schemes, disjoint sets of pilot subbands with its pilot tone of pulsing, and is used in intrasystem sector in assigned timeslot.Sector in each sub-district can be further by using its pilot tone of different orthogonal sign indicating number orthogonalization.Yet, because the sub-district is without synchronously, can be from the pilot tone of different districts at different time place incoming terminal, terminal need realize the search to these pilot pulses.And, because the sub-district is without synchronously, may disturb with pilot transmission from the sector of other sub-districts from the transfer of data of sector in the sub-district, vice versa.
For asynchronous continuous pilot transmission plan, intrasystem sector and sub-district are not synchronous, and its pilot tone of transmission on the sets of pilot subbands is being specified continuously in each sector.Equally, the sector in each sub-district can be by using its pilot tone of different orthogonal sign indicating number orthogonalization.Because the sub-district is without synchronously, terminal can need the sequential of definite each sector of recovering.
For the lock-out pulse pilot transmission schemes, the minimal degradation that the pilot tone of each sector experience is disturbed from cochannel is promptly from the interference that is assigned with other sectors of same pilot subband and orthogonal code.For synchronous continuous pilot transmission plan, the pilot tone of each sector experience cochannel disturbs the deterioration that causes, described interference is because the transfer of data of adjacent sectors on this pilot subbands causes.For asynchronous pulse/continuous pilot transmission plan, the pilot tone experience of each sector is disturbed the deterioration that causes from cochannel, described interference is owing to disturb between the transfer of data loading wave that causes of asynchronous OFDM symbol timing cause that wherein inter-carrier interference does not exist under no multipath situation.
Handle in following detailed description at the receiver of end for each of these pilot transmission schemes.
No matter the pilot transmission schemes of selecting for use, pilot subbands can be assigned to the sector in every way.In one embodiment, distributing to each sector carries out the sets of subbands of pilot transmission and fixes.In another embodiment, each sector is in the different sub-band set at different time-gap and sends its pilot tone.This embodiment can allow terminal to obtain the channel estimating of better sector.
III. system
Fig. 7 illustrates the embodiment block diagram of multi-carrier communications systems 100 interior base station 110x and terminal 120x.For simplicity, base station 110x is that an antenna is realized handling and comprising in a sector.
On down link, at base station 110x place, emission (TX) data processor 714 receives traffic data and slave controller 730 reception signaling and other data from data source 712.The format of the 714 pairs of data of TX data processor, coding, intersect and modulation (being symbol mapped) so that data modulation symbols or data symbols only to be provided.Modulator (MOD) 720 receives and with multiplexed these data symbols of pilot frequency code element, realizes the processing of requirement, and OFDM is provided code element stream.The following description of the processing of modulator 720.Transmitter unit (TMTR) 722 is handled the OFDM code element stream then so that down link signal to be provided, and they send to terminal from antenna 724 subsequently.
At terminal 120x place, a plurality of base stations are that the down link signal that a plurality of sectors send is received by antenna 752.The signal that receives is handled (for example amplification, filtering, frequency down conversion and digitlization) so that sampling to be provided through receiver unit (RCVR) 754.Demodulator (DEMOD) 760 thinks that to handle sampling with the mode of modulator 720 realization complementations the sector of recovery provides pilot frequency intensity to estimate and data symbols is estimated then.Receive (RX) data processor 762 and further handles (for example code element is gone mapping, gone to intersect and decoding) data symbols and estimate so that data after the decoding to be provided, these data are provided for data sink 764 then and store and/or offer controller 770 and further handle.
The processing of up link may be identical or different with the processing of down link.Data and signaling are handled (for example encode, intersect and modulate) so that data symbols to be provided by TX data processor 784, described code element and pilot frequency code element multiplexed and further by modulator 790 processing so that transmit symbol to be provided.Modulator 790 can be realized OFDM processing, CDMA processing etc., and this depends on the specific modulation technology that is used for up link.Transmitter unit 792 is further handled transmit symbol to generate uplink signal, and described signal is sent out from antenna 752 then.
At base station 110x place, come the uplink signal of self terminal to receive, and the signal that receives is handled so that sampling to be provided by receiver unit 738 by antenna 724.Sampling is further handled to provide data symbols to estimate by demodulator 740, and described estimation is further handled with data after the decoding that each terminal that is resumed is provided by RX data processor 742.Decoding back data can be provided for data sink 744 to store and/or to offer controller 730 with further processing.
Controller 730 and 770 is controlled at base station and the corresponding various processing unit operation of end.Memory cell 732 and 772 storages are respectively by controller 730 and 770 data and the program codes that use.
1. base station pilot is handled
Fig. 8 illustrates the block diagram of the embodiment of modulator 720.In this embodiment, pilot transmission occurs on K the sets of pilot subbands that is assigned to i sector.Pilot frequency code element N
WThe Walsh sign indicating number W of individual chip
i(n) cover and with the scrambler S that distributes to i sector
i(n) scrambler.
Generally, identical pilot frequency code element can be used for all pilot subbands or different pilot frequency code element can be used for different pilot subbands.Pilot frequency code element is based on the modulated symbol (described scheme such as BPSK, QPSK or M-QAM) that certain modulation schemes derives, i.e. the complex values of any in the signal constellation which of corresponding modulating scheme.And identical pilot frequency code element can be used by all sectors, or different pilot frequency code element can be used by different sectors.In one embodiment, be M in the system M the pilot frequency code element set that available subband definition is specific.The pilot frequency code element that use each sector depends on the sets of pilot subbands of distributing to this sector.In any case terminal has the priori of the pilot frequency code element that use the sector in the system in the system.
In modulator 720, by the pilot frequency code element p of i sector transmission
i(n) be provided for demultiplexer (Demux) 812 and be decomposed into K pilot frequency code element stream of K pilot subbands by multichannel.For each OFDM code element period, identical pilot frequency code element can be launched on all K pilot subbands, and perhaps K pilot frequency code element set can send on K pilot subbands.Under any circumstance, each of K pilot frequency code element stream is provided for corresponding TX pilot subbands processor 820, and this processor is that the pilot subbands of its distribution is handled pilot frequency code element.
In each TX pilot subbands processor 820, the pilot frequency code element p of k the pilot subbands that is assigned with
I, k(n) be provided for complex multiplier 822 and multiply by the scrambler segmentation S of k pilot subbands
I, k(n).Scrambler can accomplished in various ways.For example, scrambler can be so that each scrambler chip be applied to each the whole Walsh sequence W of (1) K pilot subbands
i(n) (for the first above-mentioned scrambler scheme), (2) a Walsh sign indicating number chip in a pilot subbands (for the second above-mentioned scrambler scheme), (3) a Walsh sign indicating number chip of all K pilot subbands, or some other the combination of (4) Walsh sign indicating number chip and pilot subbands.
K TX pilot subbands processor 820a can be identical or different to K segmentation of the scrambler chip of 820k use, and this depends on the specific scramble codes scheme of realization.For the first scrambler scheme, identical scrambler sequence is used for each of K pilot subbands, and each scrambler chip is applied to N
WIndividual continuous pilot code element, this is by at N
WKeep the constant realization of scrambler chip on the individual continuous OFDM code-element period.For the second scrambler scheme, scrambler sequence S
i(n) be divided into K scrambler segmentation (for example as above describing), segmentation of each of K pilot subbands for the second scrambler scheme.Each scrambler chip is applied to a pilot frequency code element of a pilot subbands then.
Be provided for multiplier 824 then and use Walsh sign indicating number W from pilot frequency code element behind the scrambler of multiplier 822
i(n) cover.This covering is by will be at N
WThe N that sends in the individual continuous OFDM code element period
WIndividual scrambler pilot frequency code element multiply by Walsh sign indicating number W
i(n) N
WIndividual chip multiplies each other and realizes, wherein for the example Walsh sign indicating number that illustrates in the form 3, N
W=4.The pilot frequency code element that covers is used gain G by multiplier 826 then
PilotCarry out proportional zoom, this has determined to be used for the amount of transmission power of pilot transmission.Generally, total transmitting power P of each sector or each antenna
TotalBe subjected to the constraint of code requirement for example and/or power amplifier restriction.This total transmitting power P
TotalPart be that pilot transmission is distributed, and remaining power can be used for transfer of data.The power of amount P that is used for pilot transmission
PilotSelection can minimize the Pilot Interference of other sectors simultaneously so that quicken the pilot detection of terminal in the sector/obtain to transfer of data.Pilot power P
PilotCan be fixing or variation, and gain G
PilotBased on pilot power P
PilotDetermine.Be provided for MxN switch 848 then from K TX pilot subbands processor 820a pilot frequency code element after the processing of 820k.
For nearly (M-K) the individual subband that will be used for transfer of data, be by the data symbols d of i sector transmission
i(n) be provided for demultiplexer 832 and be decomposed into nearly (M-K) individual data code element stream by multichannel.Each data symbols also is based on the modulated symbol (described scheme such as BPSK, QPSK or M-QAM) that certain modulation schemes derives.Identical or different modulation scheme can be used for pilot tone or data symbols.The sub-stream of each data symbols is provided for corresponding TX data subband processor 840, the data subband deal with data code element of described processor for distributing.Each processor 840 can be realized Walsh covering, scrambler, proportional zoom, some other processing or not do any processing.Also be provided for switch 848 from (M-K) individual data subband processor 840a data symbols after the processing of 840q.
848 pairs of switchs make these code elements be provided for the pilot tone and the data subband of its appointment from pilot frequency code element after the processing of K TX pilot subbands processor 820 and from data symbols ordering after the processing of (M-K) individual TX data subband processor 840.Switch 848 also is provided as zero signal value to each untapped subband.For each OFDM code element period, switch 848 anti-fast Flourier inversionization (IFFT) unit 850 provide N the output symbol set (comprise and handle back pilot tone and data symbols and zero) of N total subband.
In IFFT unit 850, the N of each OFDM code element period code element uses invert fast fourier transformation to be switched to time domain to obtain to comprise " conversion " back code element of N time-domain sampling.In order to eliminate the inter symbol interference (ISI) that frequency selective attenuation causes, the part of code element is repeated to form corresponding OFDM code element by Cyclic Prefix generator 852 after each conversion, and this comprises N+C
pIndividual sampling, wherein C
pIt is the hits of repetition.The part that repeats is commonly called Cyclic Prefix.The duration of a corresponding OFDM code element of OFDM code element period.Cyclic Prefix generator 852 provides OFDM code element stream for transmission on an antenna.
If the sector has a plurality of antennas, then can handle each antenna realization identical pilot tone as shown in Figure 8.Particularly, the pilot frequency code element of each antenna covers with the Walsh sign indicating number, uses the scrambler scrambler, and is multiplexed on K the sets of pilot subbands distributing to this antenna.The special pilot transmission plan that depends on realization can be distributed to the identical or different Walsh sign indicating number of a plurality of antennas, can use identical or different scrambler to antenna, and can use identical or different sets of subbands for antenna.Data symbols can be handled to transmit on a plurality of antennas, as describing in aforesaid U.S. Provisional Patent Application sequence number 60/421309 according to STTD or Alamouti scheme.
2. the terminal pilot tone is handled
Fig. 9 A illustrates the embodiment block diagram of demodulator 760a, and this demodulator can be used for aforesaid lock-out pulse pilot transmission schemes, wherein the sector in assigned timeslot with its pilot tone of pulsing.For each pilot pulse, demodulator 760a can realize handling to recover the pilot tone from a plurality of sector transmission.
In demodulator 760a, the OFDM code element that receives is provided for cyclic prefix removal unit 912, and it has removed the Cyclic Prefix that invests on each OFDM code element to obtain the corresponding code element after the conversion that receives.Code element was transformed into frequency domain with the individual code element that receives of the N that obtains N total subband after FFT unit 914 received each then and changes.NxM switch 916 provides the code element that receives of each K sets of pilot subbands to K RX pilot subbands processor 920aa to the corresponding set 918 of 920ak, and wherein each pilot subbands in the pair set has a processor 920.For the lock-out pulse pilot transmission schemes, on non-intersect sets of subbands, receive pilot tone from a plurality of sectors.RX pilot subbands processor sets can be used to each sector that will recover to realize the pilot tone processing then.(for example from different districts or bunch) can send with the different orthogonal sign indicating number in the same sub-band set because a plurality of sectors, and a plurality of RX pilot subbands processor sets can also be used to handle given sets of pilot subbands.For simplicity, in Fig. 9 A, a RX pilot subbands processor sets only is shown for each sets of pilot subbands.
The pilot tone of terminal is handled the pilot tone that realizes with the sector and is handled complementation, and further depends on the characteristic of channel.In order to improve the pilot detection performance and to distinguish the pilot tone that different sectors send better, expectation can realize coherent integration on OFDM code element period as much as possible and pilot subbands as much as possible.Yet the amount of the coherent integration that realizes in time domain and frequency domain depends on the coherence time and the coherence bandwidth of channel respectively.Particularly, the duration of coherent integration (promptly can realize the OFDM code element number of coherent integration thereon) should be less than the coherence time (being the substantially invariable duration of channel) of channel.And, comprise that the frequency range of the subband that can coherently be added should be less than the coherence bandwidth of channel.Coherence bandwidth is the substantially invariable frequency band of channel within it, and relevant with the time delay expansion of channel.
The pilot tone that illustrates in Fig. 9 A is handled and realize coherent integration on single Walsh code element period and single pilot subbands.For simplicity, the pilot tone of given sector i is handled following description.In being used for each RX pilot subbands processor 920 of sector i, k the pilot subbands that is assigned with receive code element r
k(n) be provided for multiplier 922, and multiply by the Walsh sign indicating number W of this sector i
i(n).The code element of going to cover is provided for complex multiplier 924 then and multiply by the complex conjugate S of scrambler chip
I, k *(n), it is used for k subband in n OFDM code element period by sector i.Go the mode of scrambler realization and the scrambler complementation that sector i realizes.For the first scrambler scheme, each scrambler chip is by keeping the scrambler chip at N
WThe individual continuous OFDM code element period goes up constant and is applied to N
WIndividually go to cover code element continuously.For the second scrambler scheme, a scrambler segmentation is used for each of K pilot subbands, and of being applied in a pilot subbands from multiplier 922 of each scrambler chip goes to cover code element.Going the scrambler code element to be provided for complex multiplier 926 then and multiply by the complex conjugate p of pilot frequency code element from multiplier 924
I, k *(n), this pilot frequency code element is sent on k subband by sector I in n OFDM code-element period.Output from multiplier 926 is added up on each Walsh code element period so that the pilot tone estimation of this Walsh code element period to be provided by accumulator (ACC) 928 then
Multiplier 922,924 and 926 (is 1/T with the operation of OFDM chip rate
Sym).Accumulator 928 is realized adding up with the OFDM chip rate, but for each Walsh code element period provide pilot tone estimate and each Walsh code element period begin be eliminated.Filter 930 and unit 932 (are 1/T with the operation of Walsh chip rate
w, or be 1/4T for 4 chip Walsh sequences
Sym).
Pilot tone from accumulator 928 is estimated
Can also be further by filter 930 filtering so that the estimation of the channel of k pilot subbands to be provided to sector i
Filter 930 can use accumulator, finite impulse response (FIR) (FIR) filter, infinite impulse response (IIR) filter or some other types filters to realize.Unit 932 calculates from the pilot tone of accumulator 928 to be estimated
Squared magnitude think that k the subband that sector i distributes provides the pilot frequency intensity estimation
For each OFDM code element period of pilot transmission, summer 934 receives the pilot frequency intensity of all K pilot subbands of sector i and estimates
And its summation estimated with the pilot frequency intensity that obtains this OFDM code element period
The pilot frequency intensity that accumulator 938 adds up on the part or all of pilot transmission gap is then estimated
Think that sector i provides final pilot frequency intensity to estimate
For example, accumulator 938 can be realized adding up in whole pilot pulse.Accumulator 928 is realized coherent integration and accumulator 938 realization non-coherent integrations.
If allow the coherence time of wireless channel, coherent integration can also realize on a plurality of Walsh code element periods.In this case, the pilot tone of a plurality of Walsh code element periods is estimated to be added up (for example by accumulator 928), and the estimation that produces can be provided for filter 930 and 932.If the coherence bandwidth of wireless channel allows, coherent integration can also realize (for example some or all of K pilot subbands) on a plurality of pilot subbands.In this case, can be for many pilot subbands add up, amplitude square is estimated (for example by unshowned accumulator in another Fig. 9) and offered summer 934 from the pilot tone of accumulator 928.The frequency range that comprises pilot subbands should wherein realize coherent integration less than the wireless channel coherence bandwidth on this frequency range.Can realize the pilot frequency intensity estimation of coherent integration in the frequency domain, obtain channel estimating but be generally single subband to be improved.If the coherence time of wireless channel and coherence bandwidth allow, coherent integration can also realize on a plurality of Walsh code element periods and a plurality of pilot subbands, estimates with the pilot frequency intensity that improvement is provided.
Above-mentioned pilot tone is handled the channel estimating of K the pilot subbands that sector i is provided.The channel estimating of the residue M-K of a sector i subband can obtain based on the channel estimating (for example passing through interpolation) of K the pilot subbands of sector i.Describe in U.S. Patent Application Serial Number 60/422362 and 60/427896 estimate the technology of channel estimating based on all M subbands of the channel estimating of K subband, the former is entitled as " ChannelEstimation for OFDM Communication Systems ", be filed on October 29th, 2002, the latter is entitled as " Reduced Complexity Channel Estimation for WirelessCommunications Systems ", be filed on November 19th, 2002, both are transferred to assignee of the present invention and comprise as a reference at this.Signal is estimated to be used for data demodulates and other purposes.
The channel estimating of a whole or subclass of the M of sector i available subband can be used to the transfer of data that receives from sector i to realize the coherence data demodulation.Can also obtain channel estimating for intrasystem a plurality of sectors.For each sector, pilot tone is handled the Walsh sequence W that uses with this sector
i(n), scrambler S
i(n) and pilot frequency code element p
i(n) realize.
Above-mentioned pilot tone is handled the pilot frequency intensity that sector i also is provided and is estimated.Pilot frequency intensity is estimated and can be obtained for intrasystem a plurality of sectors.The pilot frequency intensity of a plurality of sectors estimates can be used for determining to receive the best sector of transfer of data, to switch to another sector (for example for portable terminal) and other purposes of possibility from a sector.
For the lock-out pulse pilot transmission schemes, demodulator 760a only realizes the pilot tone processing in the time slot that pilot tone is sent by the sector.The channel estimating of one or more sectors can be used for realizing in period between pilot pulse the coherence data demodulation of the transfer of data that receives from one or more sectors.
Fig. 9 A illustrates example pilot tone treatment technology, and this technology can be realized by terminal.Can also use other pilot tone treatment technologies, and this within the scope of the present invention.For simplicity, the pilot tone that only shows demodulator 760a in Fig. 9 A is handled.Data processing can be realized in mode as described below by demodulator 760a.
Fig. 9 B illustrates the embodiment block diagram of demodulator 760b, and this can be used for above-mentioned synchronous continuous pilot transmission plan, and wherein each sector sends pilot tone continuously in it specifies sets of pilot subbands, and sends data on remaining subband.In the following description, demodulator 760b recovers pilot tone and the data by given sector i transmission.
In demodulator 760b, the OFDM code element that receives is handled in the above described manner by cyclic prefix removal unit 912 and FFT unit 914.Switch 916 provides the code element that receives of K pilot subbands to K RX pilot subbands processor 920a to 920k then, and the code element that provides M-K residue subband to receive to 940q to M-K Pilot Interference canceller 940a.
The mode that each RX pilot subbands processor 920 is described with Fig. 9 A is the pilot tone processing that sector i realizes a pilot subbands.Yet, because the pilot subbands of sector i can be by other sectors as data subband, coherent integration can realize on longer time slot that (for example a plurality of Walsh code element period) is to offset the interference that causes owing to other sectors of data code elements, to obtain pilot tone estimation more accurately
The coherent integration time slot is by decision channel coherence time, and should be less than this coherence time.
In each RX pilot subbands processor 920, multiplier 922,924 and 926 (is 1/T with the operation of OFDM chip rate
Sym) and the Walsh sequence W of realization and sector i
i(n), scrambler S
i(n) and pilot frequency code element p
i(n) multiplication.Accumulator 928 adds up with OFDM chip rate operation and on one or (best) a plurality of Walsh code element periods and thinks that from the output of multiplier 926 each gap of adding up provides pilot tone to estimate
Filter 930 is estimated with add up speed operation and filtration pilot tone
Channel estimating with k subband that sector i is provided
The channel estimating of all K pilot subbands can further processed (for example interpolation) to obtain the channel estimating of data subband, as mentioned above.Unit 932, adder 934 and accumulator 938 are operated with the speed that adds up and are that sector i provides pilot frequency intensity to estimate
For the continuous pilot transmission plan, demodulator 760b can handle in the free pilot tone that realizes of institute during communication session.The channel estimating of sector i can be used to be implemented in the coherence data demodulation of the transfer of data that receives on the data subband from sector i.Data processing can followingly realize.
For simplicity, have only the set of one K RX pilot subbands processor 920 and being integrated in Fig. 9 B of a M-K Pilot Interference canceller 940 to illustrate.Demodulator 760b can also realize with a plurality of RX pilot subbands processor sets and the set of a plurality of M-K Pilot Interference canceller, to handle pilot tone and the transfer of data from a plurality of sectors with setting out.
Demodulator 760a and 760b can also be used to above-mentioned asynchronous pulse/continuous pilot transmission plan to realize the pilot tone processing.If the sector is asynchronous, then terminal can need the timing of definite each sector that will recover.This can obtain by using (sliding) correlator that slides, and it is used that this is similar to cdma system.Then, the processing of each sector can realize according to the timing of this sector.Particularly FFT operation, Walsh sequence W
i(n) remove to cover and use scrambler S
i(n) the scrambler that goes is all realized according to the timing of the sector that will recover.And, coherent integration can on the longer time period, realize (for example a plurality of Walsh code element period) to offset because the interference that the data symbols that other sectors send causes, make and estimate for the sector that will recover obtains more accurately pilot tone
For the asynchronous pulse pilot transmission schemes, the pilot tone of each sector handle can followingly realize (1) in the time slot when pilot tone is sent by the sector, realize and (2) based on the timing realization of this sector.For asynchronous continuous pilot transmission plan, the pilot tone of each sector is handled and can be realized if having time in institute based on the timing of this sector.
3. the terminal Pilot Interference offsets
As mentioned above, the pilot transmission from sector in the system can be so that the subband that the pilot transmission of given sector i is used can also be used for the pilot transmission of other sectors.For this sector i, represent an interference from the pilot transmission of other sectors on its pilot subbands, if described interference is offseted effectively, can improve channel estimating and the pilot frequency intensity of this sector i and estimate.And the subband that sector i is used for transfer of data can also be used for the pilot transmission (for example for the continuous pilot transmission plan) of other sectors.For this sector i, on its data subband, represent an interference from the pilot transmission of other sectors, if being cancelled effectively, described interference can improve data performance.
For example, terminal can be from the sector 1 receives transfer of data, the pilot tone of sector 1 on sets of subbands 1, send (for example for the subband 10,20,30 of the example ofdm system that illustrates in form 2 and Fig. 2 B ... 500).This terminal is also known the pilot tone that other sectors send.Some of these pilot tones can not be sent out on sets of subbands 1, and for example adjacent sectors 2 may be gone up in sets of subbands 2 (for example subband 11,21,31...501) and send pilot tone.General sector 1 uses the terminal of nearly all not available subband in sets of subbands 1 in its overlay area to send data.Therefore, the subband (can be used for pilot transmission by sector 2) in the set 2 can be by sector 1 as data subband.Pilot transmission on the subband in the set 2 that use sector 2 can become the interference of sector 1 to transfer of data on these same sub-band.
Terminal generally knows that the pilot transmission of sector 2 on sets of subbands 2.Therefore, terminal can be estimated from subband in set 2 from the Pilot Interference of sector 2.Pilot Interference is estimated to obtain in the following manner (1) and is estimated 2 channels to the terminal of gathering each subband in 2 from the sector, (2) serve as that each subband in the set 2 generate the pilot frequency code element of handling back (promptly through scrambler and covering) with the same way as that realizes as sector 2, and (3) pilot frequency code element after with channel estimating these being handled carry out proportional zoom.The Pilot Interference of each subband is estimated to deduct the code element with the pilot tone that obtains this subband from receiving of same sub-band then to offset the back code element in the set 2 of sector 2.
Generally, can carry out downlink pilot or transfer of data when also being used for the pilot transmission of down link of another sector being used for a sector arbitrarily, realize that Pilot Interference offsets, wherein said pilot tone is that terminal is known.Generally, terminal can be known the pilot tone that another sector sends, because this information is used to make things convenient for auxiliary switching of terminal between the sector.The pilot power that the terminal general measure receives from its current service sector and are the pilot tones that the sector receives of closing on of handoff candidate from other.Pilot power is measured the sector that can be used to ask to switch to better services then by terminal.
Pilot Interference offsets can be for pilot subbands realizes estimating to obtain higher-quality pilot tone, owing to from other sectors the interference that this pilot tone causes is removed.For example, for the lock-out pulse pilot transmission schemes, all sectors send its pilot tone simultaneously, in this case, can realize that Pilot Interference offsets with the channel estimating after the improvement that obtains selected sector.Pilot Interference offsets and can also realize estimating to obtain higher-quality data symbols for data subband, has wherein removed from the interference of other sector pilot tones to this pilot tone.For simplicity, for data subband pilot cancellation is described below.
Get back to Fig. 9 B, (M-K) code element that receives of each of data subband is provided for corresponding Pilot Interference canceller 940.Each canceller 940 is estimated the pilot tone estimation that terminal receives from each interference sector, and described interference is designated will to be offseted.Each canceller 940 (1) then specifies interference sectors to obtain total Pilot Interference for all to estimate, and (2) offset from the total Pilot Interference that receives code element and estimate, thinks that the data subband of distribution provides pilot tone to offset the back code element.
Figure 10 illustrates the embodiment block diagram of Pilot Interference canceller 940x, and this Pilot Interference canceller 940a that can be used for Fig. 9 is to each of 940q.Pilot Interference offsets in frequency domain and realizes after the fast fourier transform.Canceller 940x is that a data subband realizes that Pilot Interference offsets.
In Pilot Interference canceller 940x, the code element that receives of the subband that is assigned with is provided for L Pilot Interference estimator 1020a to 1020l, wherein L can be any zero or bigger integer.Each estimator 1020 estimates to bring up at k the son that distributes the Pilot Interference of j the interference sector that is assigned with certainly, and will offer the Pilot Interference estimation for the subband and the sector of its distribution
In each estimator 1020, k the subband that is assigned with receive code element r
k(n) be provided for multiplier 1022 and multiply by the Walsh sign indicating number W that j interference sector uses
j(n).The complex conjugate S of scrambler chip is multiply by in the output of multiplier 1022 then by complex multiplier 1024
I, k *(n), described scrambler is used for k subband by j interference sector.The code element behind the scrambler of going from multiplier 1024 be multiply by the complex conjugate p of pilot frequency code element then by multiplier 1026
I, k *(n), described code element is sent on k subband by j interference sector.
Add up on each Walsh code element period by accumulator 1028 then from the output of multiplier 1026 and to think that k subband in this Walsh code element period provides pilot tone to estimate
Estimate further to think that by filter 1030 filtering k subband provides the channel estimating of j interference sector from the pilot tone of accumulator 1028
Filter 1030 can use accumulator, FIR filter or iir filter to realize.The response of filter 1030 (for example adding up the duration) can be depended on the speed of fading channel.In order to be the estimation of j interference sector derivation Pilot Interference
J the pilot frequency code element p that use the sector
I, k(n) (1) multiply by scrambler chip S by multiplier 1034
I, k(n), (2) are by multiplier 1036 usefulness Walsh sign indicating number W
j(n) cover, and (3) multiply by channel estimating by multiplier 1038
Estimate to estimate with the total Pilot Interference that obtains k subband by summer 1042 summations then from the Pilot Interference of all estimators that are assigned with 1020
Total Pilot Interference is estimated
Then by the code element r of summer 1044 from receiving
k(n) deduct in the pilot tone that obtains k subband and offset the back code element.
Get back to Fig. 9, the offseting the back code element from Pilot Interference canceller 940a to the pilot tone of 940q and offered M-K RX data subband processor 980a respectively of M-K data subband to 980q.Each processor 980 is handled pilot tone for the data subband that distributes and is offseted the back code element, the complementation that its processing mode and Fig. 8 inner treater 840 are realized.The dot product of the channel estimating of the code element after each processor 980 can also offset by the calculating pilot tone and the data subband of distribution is realized the coherence data demodulation, estimates so that data symbols to be provided
They are estimations of the data symbols that sends on this subband.The channel estimating of i the sectors of data subband that recovers can be based upon the channel estimating of pilot subbands acquisition and derive (for example using interpolation).
Multiplexer 990 receive then from RX data subband processor 980a to the data symbols of 980q and it is carried out multiplexed, so that i sectors of data symbol estimation of recovery to be provided
Above-mentioned Pilot Interference cancellation techniques can directly expand to a plurality of reception antenna situations of end.In this case, can realize identical pilot tone processing for the signal that receives that obtains from each terminal antenna.The pilot tone of each antenna offsets the back code element can also further carry out coherent demodulation so that the data symbols estimation of this antenna to be provided with channel estimating.Estimate that from the data symbols of all antennas also combination is to provide the final data symbol estimation through weighting then, described symbol estimation is decoded then.
Above-mentioned pilot transmission and Pilot Interference cancellation techniques can be realized by variety of way.For example, the pilot transmission at access point place is handled and the pilot detection of end and Pilot Interference offset processing can be with realization in hardware, software or its combination.Realize for hardware, be used to transmission to handle pilot tone and be used for the element that Pilot Interference offsets and can realize in following element: one or more application-specific integrated circuit (ASIC)s (ASIC), digital signal processor (DSP), digital signal processing appts (DSPD), programmable logic device (PLD), field programmable gate array (FPGA), processor, controller, microcontroller, microprocessor and other are used to realize in the electronic unit of above-mentioned functions or its combination.
Realize that for software pilot transmission/receptions and Pilot Interference offset processing can realization in the module that realizes function described here (for example process, function etc.).Software code can be stored in memory cell interior (for example memory cell 732 and 772 in Fig. 7) and carry out (for example controller 730 and 770) by processor.Memory cell can be implemented in the processor or processor outside, externally under the situation, it can be communicatively coupled to processor by variety of way known in the art.
Title is comprised at this and is used for reference and is used for helping some chapters and sections of location.These titles are not to be used to limit the notion of describing under the title, and these notions can be applied to other chapters and sections of whole explanation.
Those skilled in the art is further appreciated that can realizing with electronic hardware, computer software or both combinations in conjunction with the described various illustrative logical blocks of the embodiments described herein, module and algorithm steps of disclosing here.As various illustrative assemblies, square frame, module, circuit and the step 1 according to its functional elaboration.These are functional realizes specific application program and the design of depending on that whole system adopts as hardware or software actually.The technical staff can recognize the interactivity of hardware and software under these situations, and the described function that how to realize each application-specific best.
The description of above preferred embodiment makes those skilled in the art can make or use the present invention.The various modifications of these embodiment are conspicuous for a person skilled in the art, and Ding Yi General Principle can be applied among other embodiment and not exceed scope of the present invention here.Therefore, the embodiment that the present invention is not limited to illustrate here, and will meet and the principle and the novel feature the most wide in range consistent scope that disclose here.
Claims (47)
1. method that sends pilot tone in wireless multi-carrier communication system on the down link is characterized in that comprising:
For the transmission on first sets of subbands generates pilot frequency code element, wherein said first sets of subbands is used for the pilot transmission of first transmitting entity, and it is non-intersect with second sets of subbands of the pilot transmission that is used for second transmitting entity, and each in wherein said first sets of subbands comprises a frequency range to adjacent sub-bands, and this scope is less than or equal to the coherence bandwidth of wireless channel in the system;
Handle pilot frequency code element to obtain to have the pilot signal of pilot frequency code element, described pilot frequency code element is included in first sets of subbands; And
From the first transmitting entity pilot signal transmitted.
2. the method for claim 1 is characterized in that also comprising:
Handle pilot frequency code element with the pilot frequency code element after obtaining to cover with orthogonal code, and the pilot frequency code element after the wherein said covering is further processed to obtain pilot signal.
3. the method for claim 1 is characterized in that also comprising:
Handle pilot frequency code element obtaining the pilot frequency code element behind scrambler with scrambler, and wherein behind the scrambler pilot frequency code element through further handling to obtain pilot signal.
4. the method for claim 1 is characterized in that, the subband in described first sets of subbands evenly distributes on a plurality of subbands of pilot tone and transfer of data being used for by first transmitting entity carrying out.
5. the method for claim 1 is characterized in that, pilot signal from first and second transmitting entities with pulsing.
6. the method for claim 1 is characterized in that, pilot signal sends with synchronous sequence from first and second transmitting entities.
7. the method for claim 1 is characterized in that, described multi-carrier communications systems is realized OFDM (OFDM).
8. the device in the wireless multi-carrier communication system is characterized in that comprising:
Be used to be created on the device of the pilot frequency code element that transmits on first sets of subbands, wherein said first sets of subbands is used for the pilot transmission of first transmitting entity, and it is non-intersect with second sets of subbands that the pilot transmission of second transmitting entity is used, and each in wherein said first sets of subbands comprises a frequency range to adjacent sub-bands, and this scope is less than or equal to the coherence bandwidth of wireless channel in the system;
Be used to handle the device of pilot frequency code element with the pilot signal that obtains to have pilot frequency code element, described pilot frequency code element is included in first sets of subbands; And
Device from the first transmitting entity pilot signal transmitted.
9. device as claimed in claim 8 is characterized in that also comprising:
Handle the device of pilot frequency code element with orthogonal code, and the pilot frequency code element after the wherein said covering is further processed to obtain pilot signal with the pilot frequency code element after obtaining to cover.
10. device as claimed in claim 8 is characterized in that also comprising:
Handle the device of pilot frequency code element with scrambler, and pilot frequency code element is handled to obtain pilot signal through further behind the wherein said scrambler with the pilot frequency code element of acquisition behind scrambler.
11. the base station in the wireless multi-carrier communication system is characterized in that comprising:
At least one pilot processor, be used to receive and handle the designated pilot frequency code element that transmits on first sets of subbands of being used for, wherein said first sets of subbands is used for the pilot transmission of being undertaken by the base station, and it is non-intersect with employed second sets of subbands of pilot transmission that carry out another base station in the system, and each in wherein said first sets of subbands comprises a frequency range to adjacent sub-bands, and this scope is less than or equal to the coherence bandwidth of wireless channel in the system;
Converting unit is used to derive time-domain sampling, and described sampling has the pilot frequency code element after the covering that is included in described first sets of subbands; And
Transmitter unit is used to handle the pilot signal of described time-domain sampling to obtain to transmit on down link.
12. a processing receives the method for pilot tone by down link in wireless multi-carrier communication system, it is characterized in that comprising:
On first sets of subbands, receive first pilot signal from first transmitting entity, wherein said first sets of subbands is used for the pilot transmission of being undertaken by first transmitting entity, and described first sets of subbands is non-intersect with employed second sets of subbands of pilot transmission of being undertaken by second transmitting entity, and each in wherein said first sets of subbands comprises a frequency range to adjacent sub-bands, and this scope is less than or equal to the coherence bandwidth of wireless channel in the system; And
Handle described first pilot signal so that be that each interior subband of first sets of subbands obtains pilot tone estimation.
13. method as claimed in claim 12 is characterized in that also comprising:
Derive channel estimating based on each subband that the pilot tone of described subband is estimated as in described first sets of subbands.
14. method as claimed in claim 13 is characterized in that also comprising:
Channel estimating based on subband in first sets of subbands is at least one the not derivation of the subband in described first sets of subbands channel estimating.
15. method as claimed in claim 12 is characterized in that also comprising:
Pilot tone based on described first sets of subbands is estimated as the estimation of described first pilot signal derivation signal strength signal intensity.
16. method as claimed in claim 12 is characterized in that also comprising:
On described second sets of subbands, receive second pilot signal from described second transmitting entity; And
Handle described second pilot signal so that estimate for each subband in described second sets of subbands obtains pilot tone.
17. method as claimed in claim 16 is characterized in that also comprising:
Being estimated as each subband in described second sets of subbands based on the pilot tone of subband derives signal and estimates.
18. the device in the wireless multi-carrier communication system is characterized in that comprising:
On first sets of subbands, receive the device of first pilot signal from first transmitting entity, wherein said first sets of subbands is used for the pilot transmission of being undertaken by first transmitting entity, and described first sets of subbands is non-intersect with employed second sets of subbands of pilot transmission of being undertaken by second transmitting entity, and each in wherein said first sets of subbands comprises a frequency range to adjacent sub-bands, and this scope is less than or equal to the coherence bandwidth of wireless channel in the system; And
Be used to handle first pilot signal so that obtain the device of pilot tone estimation for interior each subband of described first sets of subbands.
19. device as claimed in claim 18 is characterized in that also comprising:
Pilot tone based on described subband is estimated as the device that each subband in described first sets of subbands is derived channel estimating.
20. device as claimed in claim 18 is characterized in that also comprising:
On described second sets of subbands, receive the device of second pilot signal from described second transmitting entity; And
Handle described second pilot signal so that obtain the device of pilot tone estimation for each subband in described second sets of subbands.
21. the terminal in the wireless multi-carrier communication system is characterized in that comprising:
Receiver unit, be used to handle the pilot signal that on first sets of subbands, receives, wherein said first sets of subbands is used for the pilot transmission of being undertaken by first transmitting entity, and described first sets of subbands is non-intersect with employed second sets of subbands of pilot transmission of being undertaken by second transmitting entity, and each in wherein said first sets of subbands comprises a frequency range to adjacent sub-bands, and this scope is less than or equal to the coherence bandwidth of wireless channel in the system; And
At least one pilot processor is used to handle described pilot signal so that be that each interior subband of first sets of subbands obtains pilot tone estimation.
22. a method that sends pilot tone in wireless multi-carrier communication system is characterized in that comprising:
Generate pilot frequency code element, be used on first sets of subbands of carrying out pilot transmission by first transmitting entity, sending;
Handle pilot frequency code element with the pilot frequency code element after obtaining to cover with first yard, wherein said first yard is carried out the employed second yard quadrature of pilot transmission with second transmitting entity;
Handle pilot frequency code element after the described covering to obtain pilot signal, described pilot signal has the pilot frequency code element that is included in described first sets of subbands;
Handle pilot frequency code element after the described covering to obtain the pilot frequency code element behind the scrambler with scrambler, and the pilot frequency code element behind the wherein said scrambler is further treated to obtain pilot signal, wherein said first yard comprises chip, and each chip of wherein said scrambler all is applied to pilot frequency code element; And
Launch described pilot signal from described first transmitting entity.
23. method as claimed in claim 22 is characterized in that, described first yard is the Walsh sign indicating number.
24. method as claimed in claim 22 is characterized in that, described first yard each subband that is applied in described first sets of subbands.
25. method as claimed in claim 22 is characterized in that, described scrambler is pseudorandom (PN) sign indicating number.
26. method as claimed in claim 22 is characterized in that, described first yard comprises N
WIndividual chip, and each chip of wherein said scrambler all is applied to N
WIndividual pilot frequency code element.
27. method as claimed in claim 22, it is characterized in that, described scrambler is divided into a plurality of scrambler segmentations, for each subband in first sets of subbands scrambler segmentation is arranged, and the scrambler segmentation of the pilot frequency code element of interior each subband of wherein said first sets of subbands and this subband is multiplied each other.
28. method as claimed in claim 22 is characterized in that, each chip of described scrambler is applied to a pilot frequency code element.
29. method as claimed in claim 22 is characterized in that, the subband in described first sets of subbands is used at first transmitting entity evenly distributing on a plurality of subbands of pilot tone and transfer of data.
30. method as claimed in claim 22 is characterized in that, each in described first sets of subbands comprises a frequency range to adjacent sub-bands, and this scope is less than or equal to the coherence bandwidth of wireless channel in the system.
31. method as claimed in claim 22 is characterized in that, the pilot frequency code element that sends from described first transmitting entity is different from the pilot frequency code element that sends from described second transmitting entity.
32. method as claimed in claim 22 is characterized in that, described first sets of subbands is with to carry out employed second sets of subbands of pilot transmission by the 3rd transmitting entity non-intersect.
33. method as claimed in claim 32 is characterized in that, pilot signal from described first and second transmitting entities with pulsing.
34. method as claimed in claim 32 is characterized in that, pilot signal sends from described first and second transmitting entities continuously.
35. method as claimed in claim 22 is characterized in that, pilot signal sends with synchronous sequence from described first and second transmitting entities.
36. method as claimed in claim 22 is characterized in that, pilot signal sends with asynchronous sequential from described first and second transmitting entities.
37. method as claimed in claim 22 is characterized in that, described multi-carrier communications systems is realized OFDM (OFDM).
38. the device in the wireless multi-carrier communication system is characterized in that comprising:
Generation is used for carrying out at first transmitting entity device of the pilot frequency code element that sends on the employed sets of subbands of pilot transmission;
With first yard pilot frequency code element is handled device with the pilot frequency code element after covering, wherein said first yard is carried out the employed second yard quadrature of pilot transmission with second transmitting entity;
Be used to handle the pilot frequency code element after the described covering, to obtain to have the device of the pilot signal that is included in the pilot frequency code element in the sets of subbands;
Be used for handling pilot frequency code element after the described covering to obtain the device of the pilot frequency code element behind the scrambler with scrambler, and the pilot frequency code element behind the wherein said scrambler is further treated to obtain pilot signal, wherein said first yard comprises chip, and each chip of wherein said scrambler all is applied to pilot frequency code element; And
Device from the described first transmitting entity pilot signal transmitted.
39. the base station in the wireless multi-carrier communication system is characterized in that comprising:
At least one pilot processor, being used to receive pilot frequency code element also handles with the pilot frequency code element after the acquisition covering it with first yard, wherein said pilot frequency code element is designated to be used for transmitting on the employed sets of subbands of pilot transmission being undertaken by the base station, and wherein said first yard with carry out the employed second yard quadrature of pilot transmission by another base station in the system; Pilot frequency code element after the described covering is handled with the pilot frequency code element behind the acquisition scrambler with scrambler, and the pilot frequency code element behind the wherein said scrambler is further treated to obtain pilot signal, wherein said first yard comprises chip, and each chip of wherein said scrambler all is applied to pilot frequency code element;
Converting unit is used to derive time-domain sampling, and described time-domain sampling has the pilot frequency code element after the covering that is included in the described sets of subbands; And
Transmitter unit is used to handle the pilot signal of time-domain sampling to obtain to transmit on Radio Link.
40. a processing receives the method for pilot tone by Radio Link in wireless multi-carrier communication system, it is characterized in that comprising:
Carry out receiving on employed first sets of subbands of pilot transmission first pilot signal at first transmitting entity;
Handle first pilot signal so that be code element after first transmitting entity obtains to go to cover with first yard, wherein said first yard is used for the pilot transmission of being undertaken by described first transmitting entity, and with the employed second yard quadrature of the pilot transmission of being undertaken by second transmitting entity; And
Be that first transmitting entity is handled the code element after going to cover so that estimate for each subband in described first sets of subbands obtains pilot tone.
41. method as claimed in claim 40 is characterized in that also comprising:
Derive channel estimating based on each subband that the pilot tone of described subband is estimated as in described first sets of subbands.
42. method as claimed in claim 41 is characterized in that also comprising:
Based on the channel estimating of the subband in described first sets of subbands, at least one subband in described first sets of subbands is not derived channel estimating.
43. method as claimed in claim 40 is characterized in that also comprising:
Pilot tone based on the subband in described first sets of subbands is estimated, derives the signal strength signal intensity of described first pilot signal and estimates.
44. method as claimed in claim 40 is characterized in that also comprising:
The scrambler that goes with described first transmitting entity is handled the code element after covering of going of described first transmitting entity.
45. method as claimed in claim 40 is characterized in that also comprising:
Carry out receiving on employed second sets of subbands of pilot transmission second pilot signal at described second transmitting entity;
Handle second pilot signal to obtain the code element after covering of going of described second transmitting entity with described second yard; And
For described second transmitting entity is handled the code element after going to cover so that estimate for each subband in described second sets of subbands obtains pilot tone.
46. the device in the wireless multi-carrier communication system is characterized in that comprising:
At the device that carries out receiving on the employed sets of subbands of pilot transmission pilot signal by first transmitting entity;
With first yard device of handling pilot signal with the code element after obtaining to go to cover, wherein said first yard is used for the pilot transmission of being undertaken by described first transmitting entity, and with carry out the employed second yard quadrature of pilot transmission by second transmitting entity; And
Code element after processing goes to cover is so that obtain the device of pilot tone estimation for each subband in the described set.
47. the terminal in the wireless multi-carrier communication system is characterized in that comprising:
Receiver unit is used to handle at first transmitting entity and carries out the pilot signal that receives on the employed sets of subbands of pilot transmission; And
At least one pilot processor, be used for handling pilot signal with the code element after obtaining to go to cover with first yard, and handle described code element after going to cover so that estimate for each subband in the described set obtains pilot tone, wherein said first yard is used for the pilot transmission of being undertaken by first transmitting entity, and with carry out the employed second yard quadrature of pilot transmission by second transmitting entity.
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| US43860103P | 2003-01-07 | 2003-01-07 | |
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| US10/359,811 | 2003-02-07 | ||
| US10/359,811 US7280467B2 (en) | 2003-01-07 | 2003-02-07 | Pilot transmission schemes for wireless multi-carrier communication systems |
| PCT/US2004/000326 WO2004064295A2 (en) | 2003-01-07 | 2004-01-07 | Pilot transmission schemes for wireless multi-carrier communication systems |
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| CN2009101395182A Division CN101610234B (en) | 2003-01-07 | 2004-01-07 | Pilot transmission schemes for wireless multi-carrier communication systems |
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| CN2009101395182A Expired - Lifetime CN101610234B (en) | 2003-01-07 | 2004-01-07 | Pilot transmission schemes for wireless multi-carrier communication systems |
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| CN101512998B (en) * | 2006-09-11 | 2013-05-01 | 艾利森电话股份有限公司 | Device and apparatus for detection of time-frequency frequency-hopping pattern |
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| CN100589470C (en) * | 2006-10-20 | 2010-02-10 | 北京泰美世纪科技有限公司 | A data transmitting and receiving system and method for distinguishing cell utilizing scrambling code |
| US8457315B2 (en) * | 2007-01-05 | 2013-06-04 | Qualcomm Incorporated | Pilot transmission in a wireless communication system |
| CN100534048C (en) | 2007-04-27 | 2009-08-26 | 中控科技集团有限公司 | Distributed Ethernet system and method for inspecting fault based thereon |
| CN101388686B (en) * | 2007-09-14 | 2013-08-07 | 中兴通讯股份有限公司 | Method and device implementing downlink pilot under coexistence of uni-cast and broadcast multicast service |
| US9867203B2 (en) * | 2008-07-11 | 2018-01-09 | Qualcomm Incorporated | Synchronous TDM-based communication in dominant interference scenarios |
| KR101208549B1 (en) * | 2008-08-05 | 2012-12-05 | 엘지전자 주식회사 | Reference signal transmission method for downlink multiple input multiple output system |
| US20100220651A1 (en) * | 2009-03-02 | 2010-09-02 | Mediatek Inc. | Method and apparatus for broadcasting and receiving system information in OFDMA systems |
| EP2413651A4 (en) * | 2009-03-23 | 2014-12-31 | Fujitsu Ltd | Radio communication system, base station device, terminal, and radio communication method in radio communication system |
| CN107196752A (en) * | 2009-04-28 | 2017-09-22 | 三菱电机株式会社 | Gsm |
| US9992790B2 (en) * | 2015-07-20 | 2018-06-05 | Qualcomm Incorporated | Time division duplex (TDD) subframe structure supporting single and multiple interlace modes |
| CN106549885B (en) * | 2015-12-31 | 2019-09-17 | 南方科技大学 | Channel estimation method and system |
| US10285174B2 (en) * | 2016-01-11 | 2019-05-07 | Qualcomm Incorporated | Uplink data channel design for narrowband devices |
| CN106101038A (en) * | 2016-08-04 | 2016-11-09 | 成都极比特通信技术有限公司 | Antenna structure based on filter bank multi-carrier system |
| CN111385074B (en) * | 2018-12-28 | 2023-10-17 | 中兴通讯股份有限公司 | Reference signal processing method and device |
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| CN1354917A (en) * | 1999-06-08 | 2002-06-19 | 高通股份有限公司 | Method and apparatus for mitigating interference between base stations in wideband CDMA system |
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| CN101512998B (en) * | 2006-09-11 | 2013-05-01 | 艾利森电话股份有限公司 | Device and apparatus for detection of time-frequency frequency-hopping pattern |
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| CN1751489A (en) | 2006-03-22 |
| CN101610234B (en) | 2012-04-25 |
| CN101610234A (en) | 2009-12-23 |
| UA90244C2 (en) | 2010-04-26 |
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