CN105281880A

CN105281880A - Method and apparatus for transmitting signal via relay backhaul link

Info

Publication number: CN105281880A
Application number: CN201510566572.0A
Authority: CN
Inventors: 徐翰瞥; 金学成; 李大远
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2010-01-28
Filing date: 2011-01-28
Publication date: 2016-01-27
Anticipated expiration: 2031-01-28
Also published as: JP5727515B2; CN105281880B; CA2934778C; CA2934778A1; JP2013518504A

Abstract

A method and apparatus for transmitting a signal to a relay at a Base Station (BS) in a wireless communication system are disclosed. The method includes mapping a Reference Signal (RS) to a subframe having two slots, and transmitting the subframe to the relay. Each of the slots includes a plurality of consecutive resource elements over which the RS can be spread and the plurality of consecutive resource elements are overlapped with a last Orthogonal Frequency Division Multiplexing (OFDM) symbol of the slot. If a last OFDM symbol of the subframe is not available to the relay, the RS is transmitted only in a first slot of the subframe.

Description

For the method and apparatus via relay backhaul link transmission signal

The application is the international filing date submitted on July 23rd, 2012 be the application number on January 28th, 2011 is 201180006874.2 (PCT/KR2011/000610), and denomination of invention is the divisional application of " method and apparatus for via relay backhaul link transmission signal " patent application.

Technical field

The present invention relates to radio communication, and more specifically, relate to a kind of for the method and apparatus via relay backhaul link transmission signal.

Background technology

Deploy wireless communication system widely to provide the various types of communication services comprising voice-and-data service.Generally speaking, wireless communication system is by sharing the multiple access system that available system resource (such as, bandwidth, through-put power etc.) supports the communication of multiple user between a plurality of users.This multiple access system can adopt the multiple access schemes of such as code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), OFDM (OFDMA) or single-carrier frequency division multiple access (SC-FDMA).

Summary of the invention

Technical problem

Design solve problem the object of the invention is to solve Problems existing in the method and apparatus for signal transmission efficiently in relay system.

Design solve problem another object of the present invention is to solve Problems existing in the method and apparatus for transmission of reference signals and/or data efficiently in relay system.

The object that it is possible to use the present invention to realize that one of skill in the art will appreciate that is not limited to the content that described particularly above, and by from carry out by reference to the accompanying drawings the following specifically describes in more clearly understand other object that the present invention can realize.

The solution of problem

Object of the present invention can be realized by the method being provided for transferring signals at base station (BS) place in a wireless communication system relay, and described method comprises Reference Signal (RS) and is mapped to the subframe with two time slots and by this sub-frame transmission to relay.Each in time slot is included in the multiple continuous print resource elements can expanding RS on it, and last OFDM (OFDM) Overlapping Symbol of the plurality of continuous print resource element and time slot.If the last OFDM symbol of subframe is disabled to relay, in the first time slot only in subframe, transmit RS.

In another aspect of this invention, the BS in this article in provided wireless communication system, comprises radio frequency (RF) unit and processor.Processor is suitable for RS being mapped to the subframe with two time slots, and by this sub-frame transmission to relay.Each in time slot is included in the multiple continuous print resource elements can expanding RS on it, and the plurality of continuous print resource element is overlapping with the last OFDM symbol of time slot.If the last OFDM symbol of subframe is disabled to relay, then only in the first time slot of subframe, transmit RS.

If the last OFDM symbol of subframe is available to relay, then can transmit RS in two of a subframe time slot.

Time in the plurality of continuous print resource element in a slot each can be continuous print.

The plurality of continuous print resource element can be two resource elements continuous in time in a slot each.

If only transmit RS in the first time slot of subframe, then in the second time slot of subframe, data-signal can be mapped to wherein can in multiple continuous print resource elements of extended reference signal at least partially.In this case, in the second time slot of subframe, data-signal can be mapped to the surplus resources element except the resource element overlapping with the last OFDM symbol of the subframe among multiple continuous print reference element.In the second time slot of subframe, data-signal can use to be expanded for transmitting the orthogonal code that RS uses in multiple continuous print resource element.

The beneficial effect of the invention

According to embodiments of the invention, can in relay system signal transmission efficiently.Particularly, can in relay system transmission of reference signals and/or data efficiently.

The effect that it is possible to be realized by the present invention that one of skill in the art will appreciate that is not limited to the content described particularly above, and by from carry out by reference to the accompanying drawings the following specifically describes in more clearly understand other advantage of the present invention.

Accompanying drawing explanation

Be included to provide the accompanying drawing of a further understanding of the present invention to show embodiments of the invention, and appended accompanying drawing is used for explaining principle of the present invention together with this description.

In the drawings:

Fig. 1 illustrates the network configuration for evolved universal mobile communication system (E-UMTS) system.

Fig. 2 illustrates the radio frame structure in E-UMTS system.

Fig. 3 illustrates the structure of the resource grid for radio frame.

Fig. 4 illustrates downlink subframe structure.

Fig. 5 illustrates the Signal transmissions operation in multiple-input and multiple-output (MIMO) scheme.

Fig. 6 illustrates downlink reference signal (RS) pattern in Long Term Evolution (LTE) system.

Fig. 7 illustrates demodulated reference signal (DRS) structure of adding advanced LTE (LTE-A) system to.

Fig. 8 illustrates the wireless communication system with relay.

Fig. 9 illustrates the exemplary backhaul transport in Multicast Broadcast Single Frequency rate network (MBSFN) subframe.

Figure 10 illustrates when relay could not receive last OFDM (OFM) symbol of backhaul subframe, in the exemplary issue that demodulated reference signal (DMRS) reception period produces.

Figure 11 and 12 be a diagram that the flow chart of the DMRS transmission operation of enode b (eNB) according to an embodiment of the invention.

Figure 13 be a diagram that the flow chart of the channel estimating operation of relay according to an embodiment of the invention.

Figure 14 and 15 illustrates when the last OFDM symbol of subframe is disabled to relay, the exemplary signal transmission in the second time slot of subframe.

Figure 16 be a diagram that the flow chart of the DMRS transmission operation of eNB according to another embodiment of the present invention.

Figure 17 be a diagram that the flow chart of the channel estimating operation of subscriber equipment (UE) according to another embodiment of the present invention.

Figure 18 illustrates when the second time slot forbidding DMRS for subframe transmits (Tx), the exemplary signal transmission in the second time slot of subframe.

Figure 19 is the block diagram being applicable to base station of the present invention (BS), relay or relay node (RN) and UE.

Embodiment

Now carry out detailed reference to the preferred embodiments of the present invention, the example of described the preferred embodiments of the present invention is illustrated in the accompanying drawings.Embodiments of the invention are applicable to various wireless access technology, such as code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), OFDM (OFDMA) and single-carrier frequency division multiple access (SC-FDMA).CDMA can be realized by the radiotechnics as such as general land wireless access (UTRA) or CDMA2000.TDMA can be realized by the radiotechnics as such as global system for mobile communications (GSM)/GPRS (GPRS)/enhanced data rates for gsm evolution (EDGE).OFDMA can be realized by the radiotechnics as such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wireless Fidelity (Wi-Fi)), IEEE802.16 (worldwide interoperability for microwave access (WiMAX)), IEEE802.20, evolution UTRA (E-UTRA).UTRA is a part of universal mobile telecommunications system (UMTS).Third generation partner program (3GPP) Long Term Evolution (LTE) is the part of the evolution UMTS (E-UMTS) using E-UTRA, and it adopts OFDMA for down link and adopts SC-FDMA for up link.Advanced LTE (LTE-A) is the evolution of 3GPPLTE.

Although give following description, pay close attention to 3GPPLTE/LTE-A to illustrate description, this is only exemplary and therefore should not be interpreted as limiting the present invention.

Fig. 1 shows the network configuration for E-UMTS system.E-UMTS is the evolution of wideband CDMA (WCDMA) UMTS, and 3GPP is devoted to the standardization of E-UMTS.E-UMTS is also referred to as LTE.For the details of UMTS and E-UMTS technical specification, respectively with reference to " third generation partner program; Technical specification group radio access network " version 7 and version 8.

Comprise subscriber equipment (UE) 120, enode b (eNB or e Node B) 110a and 110b with reference to figure 1, E-UMTS system and be connected to the IAD (AG) of external network at the end of evolution UMTS Terrestrial Radio Access Network network (E-UTRAN).ENB can side by side transmit for the multiple data flow to multicast service and/or unicast services.An eNB manages one or more community (such as, three communities).Community is configured to provide down link or uplink transmission services to multiple UE in bandwidth 1.4,3,5,10,15 and 20MHz.Different communities can be set to different bandwidth.ENB controls the data transmission and reception of multiple UE.For down link data, by communicating downlink schedule information, eNB notifies that UE is for the time/frequency region of bearing downlink link data, compilation scheme, size of data, the information etc. relevant with hybrid automatic repeat-request (HARQ).For uplink data, eNB by transmit uplink schedule information notify UE to UE can time/frequency region, compilation scheme, the size of data information etc. relevant with HARQ.Interface can be set up, with transmission user business or service control between eNB.Core net (CN) can comprise the AG and network node that the user for UE registers.AG manages the mobility of UE on the basis of tracking area (TA).TA comprises multiple community.

Fig. 2 illustrates the radio frame structure in E-UMTS system.

10 milliseconds of radio frames are used with reference to figure 2, E-UMTS system.Radio frame is divided into 10 subframes.Each subframe is become two time slots by Further Division, and each be 0.5ms and have multiple symbol (such as, OFDM symbol or SC-FDMA symbol) on the duration.

Fig. 3 illustrates the structure of the resource grid of the duration for a time slot.

With reference to figure 3, time slot comprises temporal multiple OFDM symbol or SC-FDMA symbol and is multiplied by multiple Resource Block (RB) in frequency.A RB has 12 × 7 (6) individual resource elements (RE).The number of the RB in time slot depends on the bandwidth arranged for community.Each unit in resource grid is called as RE.RE is the least unit of resource, comprises a subcarrier of the duration for a symbol.Although time slot and RB are shown as and comprise 7 symbols and 12 subcarriers respectively in figure 3, this is only exemplary and does not therefore limit the present invention.Such as, the number of the symbol of every time slot depends on the length of Cyclic Prefix (CP).

Fig. 4 illustrates downlink subframe structure.

With reference to figure 4, in the downlink subframe in LTE system, layer 1 (L1)/layer 2 (L2) controlled area and data field are come multiplexing with time division multiplexing (TDM).L1/L2 occupies controlled area n the OFDM symbol (such as, three of foremost or four OFDM symbol) of the foremost of downlink subframe, and the residue OFDM symbol of downlink subframe is occupied in data field.L1/L2 controlled area comprises the physical downlink control channel (PDCCH) for bearing downlink link control message, and data field comprises down-link data channel, physical down link sharing channel (PDSCH).In order to receiving downlink signal, UE reads downlink schedule information from PDCCH.Then UE carrys out receiving downlink data on PDSCH based on the resource allocation information indicated by downlink schedule information.For the resource (that is, PDSCH) of UE scheduling is distributed on the basis of RB or on the basis of RB group.

PDCCH the information relevant with the Resourse Distribute being used for transmission channel, paging channel (PCH) and downlink sharied signal channel (DL-SCH), uplink scheduling are permitted and HARQ information delivery to UE.The control information that PDCCH carries is commonly referred to as down link control information (DCI).Various DCI format defines according to the content of DCI.

Table 1 illustrates the DCI format 0 for uplink scheduling.

Table 1

[table 1]

Field	Bit	Annotation
			Form	1	Up link license or line link are specified
Frequency hopping mark	1	Frequency frequency hopping ON/OFF
			RB specifies	7	Be assigned to the Resource Block of PUSCH
MCS	5	Modulation scheme, compilation scheme etc.
			New data indicator	1	Switch for each new transmission block
TPC	2	The power of PUSCH controls
			DMRS cyclic shift	3	The cyclic shift of demodulated reference signal
CQI request	1	CQI feedback is asked by PUSCH
			RNTI/CRC	16	The 16 bit RNTI encoded with including in CRC
Fill	1	Form 1A is mated in size in order to ensure form 0
			Amount to	38	-

* MCS: modulation and compilation scheme.

* TPC: transmitting power controls

* RNTI: radio network temporary identifier

* CRC: CRC

For the UE which specify PDCCH is identified by RNTI.Such as, assuming that the CRC of PDCCH is sheltered by RNTIA, and PDCCH sends uplink resource allocation message B (such as, frequency location) and transport format information C is (such as, transmission block size, modulation scheme, compiling information etc.), UE uses they self the RNTI in community to monitor PDCCH, and the UE with RNTIA carrys out transmitting uplink signals based on the information B obtained from the PDCCH with RNTIA and C.

Fig. 5 illustrates the exemplary signal transmission operation according to multiple-input and multiple-output (MIMO) scheme.

With reference to figure 5, scrambler 301 pairs of code words carry out scrambling.Each code word comprises the bit stream of the compiling corresponding with transmission block.Code word through scrambling, according to the type of signal transmission and/or channel status, is modulated to complex symbol with binary phase shift keying (BPSK), quarternary phase-shift keying (QPSK) (QPSK), 16 yuan of quadrature amplitude modulation (16QAM) or 64 yuan of quadrature amplitude modulation (64QAM) by modulation mapper 302.Complex symbol is mapped to one or more layer by layer mapper 303.

When the Signal transmissions by individual antenna, a code word is mapped to a layer.When the Signal transmissions by multiple antenna, depend on that transmission plan code word can be different to layer mapping relations.Table 2 and table 3 illustrate exemplary code word to layer mapping relations.

Table 2

[table 2]

Table 3

[table 3]

The code word that table 2 describes for spatial reuse maps to layer, and the code word that table 3 describes for transmission diversity maps to layer.In table 2 and table 3, x (a) (i) represents i-th symbol with the layer of index a, and d (a) (i) represents i-th symbol with the code word of index a.

As pointed out from table 2 and table 3, a code word can be mapped to a layer on the basis of symbol.But as in the second situation of table 3, a code word can be assigned to nearly four layers.In distributed code word maps to layer, the symbol of each code word is sequentially mapped to layer.

Although table 2 and table 3 are that this is illustrative based on nearly two code words and the nearly supposition of four layers.Therefore system is depended on, can be different for the code word of Signal transmissions and the maximum number of layer.

The signal be multiplied with the pre-coding matrix selected according to channel status, and is distributed to transmit antenna by the signal times that layer maps by precoder 304.The signal transmission being used for corresponding antenna is mapped to time-frequency RE by RE mapper 305.Then ofdm signal generator 306 is by the signal transmission of corresponding antenna transmission through mapping.

Fig. 6 illustrates downlink reference signal (RS) pattern in LTE system.

With reference to figure 6, the down link RS of two types is defined for the unicast services in LTE system, using channel condition information collection and measurement as the public RS (CRS) 0 to 3 of target, such as, for taking Data Modulation as transfer and the specific RS of UE of target.The specific RS of UE is also referred to as special RS (DRS).The specific RS of UE is used to carry out demodulation to Beam-formed data.CRS is used to both channel information collection and data demodulates.CRS is that community is specific, and is transmitted by the whole frequency band in each subframe.Because LTE system supports nearly four transmittings (Tx) antennas on the uplink, can transmit according to the number of Tx antenna at eNB place for the CRS reaching four antenna ports.In LTE system, CRS is transmitted by antenna port 0 to 3, and the specific RSD of UE is transmitted by antenna port 5.

Nearly eight Tx antennas should be able to be supported on the uplink from the lte-a system of LTE system evolution.Therefore, lte-a system should support the RS for reaching eight Tx antennas.Owing to only defining down link RS for reaching four Tx antennas in LTE system, so when eNB has four to eight down link Tx antennas in lte-a system, RS should be defined extraly for extra antenna port.

Fig. 7 illustrates the exemplary patterns of the demodulated reference signal (DMRS) adding lte-a system to.When signal is by multiple antenna transmission, DMRS is used to the specific RS of UE every layer signal being carried out to demodulation.DMRS is used to the demodulation of PDSCH and relay-PDSCH (R-PDSCH).Because lte-a system uses nearly eight Tx antennas, so it needs nearly eight layers and the DMRS for corresponding layer.For convenience's sake, the DMRS for layer 0 to 7 is called as DMRS (layer) 0 to 7.

With reference to figure 7, come multiplexing with code division multiplexing (CDM) for the DMRS of two or more layers on identical RE.In order to more concrete, the DMRS for corresponding layer uses extended code (such as, the such as orthogonal code of Wash code or discrete Fourier transform (DFT) code) to expand, and is then multiplexed in identical RE.Such as, for the DMRS of layer 0 be multiplexed in identical RE for the DMRS of layer 1.Particularly, the DMRS for layer 0 and layer 1 uses orthogonal code to expand in two OFDM symbol 12 and 13 at subcarrier 1 (k=1) place.That is, the DMRS for layer 0 and layer 1 uses the code in time with spreading factor (SF)=2 to expand, and multiplexing in identical RE in each time slot.Extended code for the DMRS of layer 0 and layer 1 can be such as [+1+1] and [+1-1] respectively.Similarly, use different orthogonal codes to expand with the DMRS of layer 3 in identical RE for layer 2.DMRS for layer 4,5,6 and 7 is being expanded with using the code orthogonal with the extended code of the DMRS for layer 0,1,2 and 3 in the RE that 1 and DMRS2 and 3 are occupied by DMRS0.For nearly four layers, the code with SF=2 is used to DMRS, but for the layer of five or more, the code with SF=4 is used to DMRS.In lte-a system, the antenna port for DMRS is given 7,8 ..., n+6} (n is the number of layer).

Table 4 lists the sequence spreading for antenna port 7 to 14 defined in LTE-A below.

Table 4

[table 4]

Reference table 4, the identical orthogonal code with length 2 repeats in for each in the orthogonal code of antenna port 7 to 10.Therefore, the orthogonal code with length 2 is used in for nearly four layers timeslot-level.For the layer of five or more, employ the orthogonal code with length 4 at sub-frame level place.

Fig. 8 illustrates the wireless communication system with relay.Relay or relay node (RN) have extended the coverage of eNB, or be installed in shadow region with thus improve service reliably.

With reference to figure 8, wireless communication system comprises eNB, relay and UE.UE and eNB or relay communicate.For convenience's sake, the UE carrying out communicating with eNB is called as grand UE, and is called as relay UE with the UE that relay carries out communicating.Communication link between eNB and grand UE and the communication link between relay and relay UE are hereinafter referred to as grand access link and relay access link.Communication link between eNB and relay is called as back haul link.

Fig. 9 illustrates the exemplary backhaul transport in Multicast Broadcast Single Frequency Network (MBSFN) subframe.For relay in band, eNB works in relay to the identical frequency band of UE link (that is, relay access link) to relay link (that is, back haul link).When relay transfer signals to UE simultaneously its just from eNB Received signal strength or vice versa, the transmitter and receiver of relay interferes with each other.Therefore, may be limited to simultaneous eNB in identical frequency resource to transmit to relay and relay to UE.For this reason, back haul link and relay access link divided in time division multiplexing (TDM).In lte-a system, back haul link is set up in the MBSFN subframe, to support the measurement of the old LTEUE being arranged in relay district ((fake) MBSFN of forgery).If subframe is used Signal transmissions by as MBSFN sub-frame, then UE only receive subframe controlled area (ctrl) and therefore relay the data field of subframe can be used to configure back haul link.

embodiment 1

Due to the reception/transmission (Rx/Tx) of the propagation delay between eNB and relay, relay switch, Operation system setting, relay may not receive the last OFDM symbol of backhaul subframe.This is because relay should be switched to Tx pattern in the moment of last OFDM symbol from Rx pattern, so that transmit the first OFDM symbol of next subframe.

Figure 10 illustrates when relay could not receive the last OFDM symbol of backhaul subframe, in the problem that DMRS reception period produces.

With reference to Figure 10, if relay could not receive the last OFDM symbol of the index 13 with backhaul subframe, then relay does not receive the part of the RE distributing to DMRS.Described by earlier in respect of figures 7, the DMRS for two or more layers shares identical RE in CDM.Therefore, if relay does not receive OFDM symbol 13, then the RE carrying DMRS in OFDM symbol 12 is not useful in channel estimating.When not having the RE of OFDM symbol 13, relay can not be separated in multiple DMRS multiplexing in the RE of OFDM symbol 12 and 13 by going to expand.Therefore, the DMRSRE of OFDM symbol 12 causes unnecessary expense to backhaul transport and reception, thus waste resource.

In order to avoid this problem, the DMRSRE of OFDM symbol last for second of subframe can be used as data RE by relay, if relay can not receive the last OFDM symbol of subframe.Such as, if relay can not receive OFDM symbol 13 as illustrated in Figure 10, then eNB transmission of data signals in the DMRSRE of OFDM symbol 12, and relay is to the decoding data of himself comprising the data carried in the DMRSRE of OFDM symbol 12.In this case, relay only uses the DMRSRE in the first time slot of subframe to perform channel estimating, and based on the decoding data of this channel estimating to the first and second time slots.That is, if relay can not receive the last OFDM symbol of subframe, then only in the first time slot of subframe, DMRS is transmitted.Therefore, it is possible to improve the utilization of radio resource.

Figure 11,12 and 13 be a diagram that the course diagram of signal processing operations according to an embodiment of the invention.Particularly, Figure 11 and 12 illustrates the DMRS transmission operation at eNB place, and Figure 13 illustrates the channel estimating operation at relay place.

The DMRS sequence (or DMRS sequence) (S1110) being used for every layer is generated with reference to Figure 11, eNB.DMRS sequence can be but be not limited to pseudo random sequence, Zadoff-chu sequence or constant amplitude zero auto-correlation (CAZAC) sequence.Such as, with reference to the generation of the RS sequence for antenna port 5 in old LTE system, DMRS sequence can be defined as

Mathematics Fig. 1

[mathematical expression 1]

r (m) = \frac{1}{\sqrt{2}} (1 - 2 \cdot c (2 m)) + j \frac{1}{\sqrt{2}} (1 - 2 \cdot c (2 m + 1))

Wherein m is the integer of 0 or larger, and c (m) is the pseudo random sequence provided by [equation 2].Pseudo random sequence is defined by golden formula (Gold) sequence of length 31.

Mathematics Fig. 2

[mathematical expression 1]

c(n)＝(x ₁(n+N _C)+x ₂(n+N _C))mod2

x ₁(n+31)＝(x ₁(n+3)+x ₁(n))mod2

x ₂(n+31)＝(x ₂(n+3)+x ₂(n+2)+x ₂(n+1)+x ₂(n))mod2

Wherein Nc=1600 and n=1,2 ..., 30.First gold medal formula sequence can be initialized to

x ₁(0)＝1，x ₁(n)＝0

And the second gold medal formula sequence can be initialized to

N _srepresent time slot index,

n _s

represent community ID, and be constant.

Then eNB determines whether relay can use the last symbol (S1120) of subframe.How can configure according to the sub-frame boundary of eNB and relay, make in a different manner and determining.Therefore, whether last symbol is available can control (RRC) signaling by system information or radio resource and indicate to relay.If the last symbol of subframe is available to relay, then eNB transmits DMRS (S1130) in the first and second time slots of subframe.In this case, DMRS can be transmitted in mode illustrated in Fig. 7.On the other hand, if the last sequence pair relay of subframe is disabled, then eNB only transmits DMRS (or multiple DMRS) (S1140) in the first time slot of subframe.In other words, the DMRS (or multiple DMRS) in the second time slot of subframe is not transferred to relay by BS.In this case, data (R-PDSCH) can be mapped to the DMRSRE of the second time slot be intended that for relay.The transmission process of DMRS can include but not limited to precompile, RE maps and ofdm signal generates.

Differently can operate according to signal receiver with reference to Figure 12, BS.For convenience's sake, assuming that relay can not use the last OFDM symbol of subframe.ENB is substantially to operate with illustrated similar fashion in Figure 11.First, eNB generates the DMRS sequence (or multiple DMRS sequence) (S1210) being used for every layer.Then eNB determines that receiving terminal is to receive DMRS (or multiple DMRS) (S1220).If DMRS will be transferred to grand UE by eNB, then BS will such as transmit DMRS (S1230) in mode illustrated in Fig. 7 in the first and second time slots of subframe.On the other hand, if DMRS will be transferred to relay by eNB, then DMRS will only be transferred to relay (S1240) by eNB in the first time slot of subframe.That is, in the second time slot of subframe, DMRS is not had to be transferred to relay.In this case, data (R-PDSCH) can be mapped to the DMRSRE of the second time slot of the subframe be intended that for relay.Although describe the process of Figure 11 and 12 independently, they can be combined into a process.

With reference to Figure 13, relay receives the subframe (S1310) comprising DMRS (or multiple DMRS) from eNB.Subframe is backhaul subframe, preferably MBSFN sub-frame.Its last symbol (S1320) that whether can use subframe determined by relay.Whether relay can use the last symbol of subframe to come pre-determining or instruction by system information or RRC signaling.If relay can use the last symbol of subframe, then relay is used in the DMRS (or multiple DMRS) received in the first and second time slots of subframe and performs channel estimating (S1330).In this case, DMRS (or multiple DMRS) can be received in mode illustrated in Fig. 7.On the other hand, if relay can not use the last symbol of subframe, then relay performs channel estimating (S1340) based on the DMRS received in the first time slot of subframe (or multiple DMRS).That is, in the second time slot of subframe, DMRS is not received.In this case, data (R-PDSCH) are mapped to the DMRSRE of the second time slot of the subframe be intended that for relay.

Figure 14 and 15 illustrates when the last OFDM symbol of subframe is unavailable to relay, the exemplary signal transmission in the second time slot of subframe.When performing aforesaid operation, can side by side transmit the direct link signal of the UE for being directly connected to eNB and the returned signal for relay by the different layer (multiuser MIMO (MU-MIMO)) in identical RB.In this case, extra operation is needed to go expansion to help UE to carry out DMRS accurately.For this reason, the backhaul data signal in OFDM symbol 12 uses the CDM code being used for the DMRS corresponding with the layer of backhaul data signal to expand, and transmits in the DMRSRE of OFDM symbol 13.This means that eNB uses and expand data-signal for back haul link for the CDM code of the DMRS corresponding with the layer of the data-signal in OFDM symbol 12 and 13.

Refer to figs. 14 and 15, assuming that returned signal uses layer 0 and direct link signal use layer 1 in MU-MIMO.Also suppose that the signal of layer 0 and 1 uses the CDM code [w respectively in two continuous print DMRSRE _0,0w _0,1] and [w _1,0w _1,1] expand.If data-signal S1,12 transmit by as the returned signal at subcarrier 1 (k=1) place in OFDM symbol 12, then the signal w at subcarrier 1 place of eNB transmission in OFDM symbol 12 _0,0* S _1,12with the data-signal S at subcarrier 1 place in OFDM symbol 13 _1,12, w _0,1* S _1,12extended version.In order to help relay data detection signal, back haul link DMRS extended code for OFDM symbol 12 and OFDM symbol 13 experiences suitable phase rotated, the symbol phase of extended code is made to be 0 (that is, use CDM code [1w in OFDM symbol 12 _0,1/ w _0,0] with thus in the examples described above by S1,12 are multiplied by 1).

From the angle of relay, relay abandons the last symbol of subframe simply and carries out demodulate/decode to R-PDSCH, considers that data-signal is similarly carried in the DMRSRE of the second last OFDM symbol of subframe.Simultaneously, from the angle of UE being directly connected to eNB, if transmit the returned signal using the MU-MIMO operation for the signal of UE in DMRSRE, then returned signal uses the code orthogonal with the DMRS of UE to expand, and no matter returned signal is data-signal or RS.Therefore, UE goes expansion to the signal in its DMRSRE, and uses and gone the signal expanded to perform channel estimating, as when its signal by use for the signal of another UE during MU-MIMO operation do.

Aforesaid operations is also applicable to the subframe in the CP situation of expansion with 12 OFDM symbol.

embodiment 2

When UE is directly connected to eNB, that is, access link is based upon between UE and eNB, and eNB transmits DMRS in two time slots of subframe, as illustrated in fig. 7.But in any case, DMRS can be transmitted in two of a subframe time slot.Such as, if channel changes at leisure or static state, even if the channel then using the DMRS in time slot to estimate in another time slot, data demodulates also may not go wrong.Therefore, in this embodiment, the DMRSTx in time slot by optionally enable or forbidding.Therefore, it is possible to reduce DMRS expense.

Figure 16 and 18 illustrates signal processing operations according to another embodiment of the present invention.Particularly, Figure 16 illustrates the DMRS transmission operation of eNB, and Figure 17 illustrates the channel estimating operation of UE.

The DMRS sequence (or multiple DMRS sequence) (S1610) being used for every layer is generated with reference to Figure 16, eNB.DMRS sequence can be but be not limited to pseudo random sequence, Zadoff-chu sequence or CAZAC sequence.Such as, generate for the RS sequence of antenna port 5 with reference in old LTE system, DMRS sequence can use [equation 1] and [equation 2] defines.

Then whether disabled (S1620) BS determines DMRSTx in the second time slot of the subframe of UE.DMRSTx forbidding/enablely can be arranged by more high-rise (such as, rrc layer) or physical layer.DMRSTx forbidding/enable can by every way with Signal transmissions to UE.Such as, DMRSTx forbidding/enable semi-statically can be indicated to UE by more high-level signaling (such as, RRC signaling).In addition, DMRSTx forbidding/enablely can pass through physical layer signaling (such as, via the PDCCH distributed for DL) and be dynamically indicated to UE.In addition, instruction DMRS forbid the information that is allowed to and can be transmitted by more high-level signaling about the beginning of DMRS forbidding and the information of duration, and the DMRSTx of reality forbidding/enable can be indicated by physical layer signaling.DMRSTx forbidding/enable can to get off setting considering the situation of channel status (such as, whether channel status is (partly) static state).

If DMRSTx is not disabled, that is, it has been enabled for UE in the second time slot of subframe, then eNB is such as in mode illustrated in Fig. 7, in the first and second time slots of subframe, DMRS (or multiple DMRS) is transferred to UE (S1630).On the other hand, if DMRSTx is disabled in for second time slot of UE, then eNB only transmits DMRS (or multiple DMRS) (S1640) in the first time slot of subframe.That is, in the second time slot of subframe, DMRS is not had to be transmitted.In this case, data (PDSCH) can be mapped to the position of the DMRS in the second time slot of subframe.The transmission process of DMRS can include but not limited to precompile, RE maps and ofdm signal generates.

Receive the subframe (S1710) comprising DMRS (or multiple DMRS) from eNB with reference to Figure 17, UE.UE determines whether DMRSTx is forbidden (S1720) by the second time slot for subframe.DMRSTx forbidding/enablely can to arrange by reference to the various types of signalings described by Figure 16.If DMRSTx is enable by the second time slot for subframe, then UE is used in the DMRS (or multiple DMRS) received in the first and second time slots of subframe and performs channel estimating (S1730).In this case, DMRS (or multiple DMRS) can be received in mode illustrated in Fig. 7.On the other hand, if DMRSTx is forbidden by the second time slot for subframe, then UE performs channel estimating (S1740) based on the DMRS received in the first time slot of subframe (or multiple DMRS).That is, in the second time slot of subframe, DMRS is not received.In this case, data (PDSCH) can be mapped to the position of the DMRS in the second time slot of subframe.

Figure 18 illustrates when DMRSTx is forbidden by the second time slot for subframe, the exemplary signal transmission in the second time slot of subframe.For convenience's sake, assuming that in MU-MIMO grand UEA use layer 0 and grand UEB uses layer 1.Also suppose that the signal of layer 0 and 1 uses the CDM code [w respectively in two continuous print DMRSRE _0,0w _0,1] and [w _1,0w _1,1] expand.Also suppose that the DMRSTx in the second time slot of subframe is forbidden by for UEA, and enable for UEB.

With reference to Figure 18, if data-signal Sk, 12 will be transferred to UEA at subcarrier k (k=1,6,11) place in OFDM symbol 12, then eNB transmits in OFDM symbol 12 at the signal w at subcarrier k place _0,0* S _{k, 12}with in OFDM symbol 13 at the signal w at subcarrier k place _0,0* S _{k, 12}, w _0,1* S _{k, 12}extended version.In order to help UEA data detection signal, the direct link DMRS extended code for OFDM symbol 12 and OFDM symbol 13 experiences suitable phase rotated, makes the symbol phase of extended code be 0 (such as, employ CDM code [1w in OFDM symbol 12 _0,1/ w _0,0]).

Therefore, UEA only abandons the DMRSRE in the last OFDM symbol of subframe simply and carries out demodulate/decode to PDSCH, considers that data-signal is also carried in the DMRSRE of the second last OFDM symbol of subframe.In addition, after the signal carried in the DMRSRE of the second time slot being gone to expansion, UEA can carry out demodulate/decode to PDSCH.UEA uses the DMRS of the first time slot, for the PDSCH demodulation of the first/the second time slot.

In other method (not shown), eNB can transmit the data-signal Sk at the subcarrier k place in OFDM symbol 12, and 12 and the different data-signal Sk at subcarrier k place in OFDM symbol 13,13.That is, each DMRSRE of the second time slot can be used to PDSCH transmission, and without any constraint.In this case, UEA can perform PDSCH demodulate/decode, considers to transmit data-signal in all DMRSRE of the second time slot.

Meanwhile, UEB supposition use be used for the signal of UEB and MU-MIMO operation and the signal for UEA transmitted in DMRSRE uses the code orthogonal with the DMRS of UEB to expand, and be data-signal or RS regardless of the signal for UEA.Therefore, after the signal in the DMRSRE to the second time slot goes expansion, UEB performs channel estimating.

Above-mentioned operation is also applicable to the subframe when the CP expanded with 12 OFDM symbol.Although in the second time slot of subframe, give foregoing description in the context of DMRSTx enables/disables, if be provided with DMRSTx enables/disables for the first time slot of subframe, identical situation has also been applicable to the first time slot of subframe.The time slot that DMRSTx is applied to can also be changed according to pre-placing graphic pattern or by signaling.Such as, DMRSTx disabled for time slot can indicate by more high-level signaling (such as, RRC signaling) or via the PDCCH distributed for DL (such as, for PDCCH that PDSCH dispatches).

Figure 19 is the block diagram being applicable to base station of the present invention (BS), RN and UE.

With reference to Figure 19, wireless communication system comprises BS110, RN120 and UE130.

BS110 comprises processor 112, memory 114 and RF unit 116.Can configuration processor 112 to realize process of the present invention and/or method.Processor 114 is connected to processor 112 and stores each bar information relevant with the operation of processor 112.RF unit 116 is connected to processor 112 and transmission and/or reception RF signal.Relay 120 comprises processor 122, memory 124 and RF unit 126.Can configuration processor 122 to realize process of the present invention and/or method.Processor 124 is connected to processor 122 and stores each bar information relevant with the operation of processor 122.RF unit 126 is connected to processor 122 and transmission and/or reception RF signal.UE130 comprises processor 132, memory 134 and RF unit 136.Can configuration processor 132 to realize process of the present invention and/or method.Processor 134 is connected to processor 132 and stores each bar information relevant with the operation of processor 132.RF unit 136 is connected to processor 132 and transmission and/or reception RF signal.BS110, relay 120 and/or UE130 can have single or multiple antenna.

The embodiments of the invention described hereinafter are combinations of element of the present invention and feature.Unless otherwise mentioned, otherwise element or feature can be considered to optionally.Each element or feature can when not realizing with when other element or Feature Combination.In addition, embodiments of the invention can be constructed by the part of composite component and/or feature.The order of operation described in an embodiment of the present invention can be rearranged.Some structures of any one embodiment can be included in another embodiment, and can replace with the correspondence structure of another embodiment.Those skilled in the art is apparent that, the claim do not quoted each other clearly in the following claims can exist as the combination of embodiments of the invention, or is included as the new claim by the subsequent correction after the application is submitted.

In an embodiment of the present invention, centered by the data transmission and reception relation between BS, relay and MS, description has been made.In some cases, the specific operation being described as being performed by BS can be performed by the upper node of BS.That is, it is evident that, in the network be made up of the multiple network nodes comprising BS, the various operations performed for the communication with MS can be performed by BS or the network node except BS.Term ' fixed station ', ' Node B ', ' replacement such as base station (BS) ', ' access point ' can be used in term ' eNB '.Term ' mobile radio station (MS) ', ' replacement such as mobile subscriber station (MSS) ', ' mobile terminal ' can be used in term ' UE '.

Embodiments of the invention can be realized by various mode such as hardware, firmware, software or its combination.In hardware configuration, method can be passed through one or more application-specific integrated circuit (ASIC) (ASIC), digital signal processor (DSP), digital signal processor (DSPD), programmable logic device (PLD), field programmable gate array (FPGA), processor, controller, microcontroller, microprocessor etc. and realizes according to an embodiment of the invention.

In firmware or software merit rating, embodiments of the invention can realize with the form of module, process, function etc.Such as, software code can be stored in a memory cell, and is performed by processor.Memory cell is positioned at inside or the outside of processor, and can transfer data to processor via various well-known mode and receive data from processor.

One of skill in the art will appreciate that, when not deviating from spirit of the present invention and fundamental characteristics, the present invention can with except state herein those except other ad hoc fashion realize.Therefore above-described embodiment is interpreted as illustrative and nonrestrictive in all respects.Scope of the present invention should be determined by claims and their legal equivalents, but not is determined by foregoing description, and all changes of the meaning and full scope of equivalents that fall into claims are all intended to be included in the present invention.

Industrial usability

The present invention relates to a kind of wireless communication system.Particularly, the present invention is applicable to the method and apparatus for carrying out signal transmission in a wireless communication system via relay back haul link.

Claims

1., in a wireless communication system by a method for relay Received signal strength, described method comprises:

By the reference signal of described relay from base station is received in the subframe with the first time slot and the second time slot,

Wherein, each in described first time slot and the second time slot is included in the multiple continuous print resource elements allowing the described reference signal of expansion on it, and latter two orthogonal frequency division multiplex OFDM Overlapping Symbol of described multiple continuous print resource element and corresponding time slot, and

Wherein, if the last OFDM symbol of described subframe is not useable for the transmission from described base station to described relay, then only in described first time slot of described subframe, receive described reference signal, and the middle at least partially of described multiple continuous print resource elements in described second time slot receives data-signal.

2. method according to claim 1, wherein, if the last OFDM symbol of described subframe can be used for the transmission from described base station to described relay, then all receives described reference signal in first time slot and the second time slot of described subframe.

3. method according to claim 1 wherein, the time in each in described first time slot and the second time slot of described multiple continuous print resource element is continuous print.

4. method according to claim 1, wherein, described multiple continuous print resource element is two resource elements continuous in time in each in described first time slot and the second time slot.

5. method according to claim 1, wherein, in described second time slot of described subframe, described multiple continuous print resource element correspond to not overlapping with the last OFDM symbol of the described subframe among described multiple continuous print resource element resource element at least partially.

6. method according to claim 1, wherein, utilizes orthogonal code to expand described reference signal.

7. method according to claim 1, wherein, in described second time slot of described subframe, described data-signal utilizes the orthogonal code used for expanding described reference signal in described multiple continuous print resource element to expand.

8. a relay in a wireless communication system, described relay comprises:

Radio frequency unit; And

Processor, described processor is operably connected to described RF unit,

Wherein, described processor is configured to control described RF unit and receives the reference signal had the subframe of the first time slot and the second time slot from base station,

9. relay according to claim 8, wherein, if the last OFDM symbol of described subframe can be used for the transmission from described base station to described relay, then all receives described reference signal in first time slot and the second time slot of described subframe.

10. relay according to claim 8 wherein, the time in each in described first time slot and the second time slot of described multiple continuous print resource element is continuous print.

11. relays according to claim 8, wherein, described multiple continuous print resource element is two resource elements continuous in time in each in described first time slot and the second time slot.

12. relays according to claim 8, wherein, in described second time slot of described subframe, described multiple continuous print resource element correspond to not overlapping with the last OFDM symbol of the described subframe among described multiple continuous print resource element resource element at least partially.

13. relays according to claim 8, wherein, utilize orthogonal code to expand described reference signal.

14. relays according to claim 8, wherein, in described second time slot of described subframe, described data-signal utilizes the orthogonal code used for expanding described reference signal in described multiple continuous print resource element to expand.