CN102055702B - Transmission method, base station, relay station and system for down link demodulation reference signal - Google Patents

Abstract

The invention provides a transmission method for a down link demodulation reference signal. In the method, a down demodulation reference signal of a relay link can be sent on an orthogonal frequency division multiplexing (OFDM) symbol which can be received by a relay station, wherein the OFDM symbol does not comprise an OFDM symbol which is mapped with a public reference signal. The invention also provides a base station, a relay station and a system. In the invention, the down demodulation reference signal of the relay link can be sent.

Description

The transmission method of down link demodulation reference signal, base station, relay station and system

Technical field

The present invention relates to moving communicating field, in particular to a kind of transmission method, base station, relay station and system of down link demodulation reference signal.

Background technology

At present, the demand for development of mobile communication is to support higher transmission rate, more perfect signal to cover and higher resource utilization.In order to reach high transfer rate, next generation mobile communication system will adopt higher frequency bandwidth for transmission signal, and higher frequency bandwidth will be brought larger path loss simultaneously, affects the network coverage.Relaying (Relay) technology can increase covering and balance and increase cell throughout, and, via node (RelayNode, be called for short RN) than base station, have relatively little deployment cost, therefore, relaying is regarded as Long Term Evolution (Long Term Evolution, referred to as LTE) evolution system-senior Long Term Evolution (LTE-Advanced, be called for short LTE-A) system in a key technology.

LTE/LTE-A system is basis with OFDM (Orthogonal Frequency Division Multiplexing, OFDM) technology.In ofdm system, when the communication resource is-form of bidimensional frequently.For example, in LTE system, the communication resource of down link be take frame (frame) as unit division on time orientation, and each radio frames (radio frame) length is 10ms, comprise the subframe that 10 length are 1ms (sub-frame), as shown in Figure 1.According to CP (Cyclic Prefix, Cyclic Prefix, abbreviation CP) difference of length, each subframe can comprise 14 or 12 OFDM symbols, when subframe adopts common CP (Normal CP) length, in subframe, comprise 14 OFDM symbols, when subframe adopts expansion CP (Extended CP) length, in subframe, comprise 12 OFDM symbols.In frequency direction, resource be take subcarrier (sub-carrier) as unit division, specifically in communication, the least unit that resource is distributed is RB (Resource Block, Resource Block), a PRB (Physical RB, Physical Resource Block) of corresponding physical resource.A PRB comprises 12 subcarriers at frequency domain.On each OFDM symbol, the resource of a corresponding subcarrier is called resource element (Resource Element is called for short RE).

After introducing relay station, be equivalent to the transmission of data many a jumping, take double bounce system as example, the communication pattern of base station-terminal has originally become the communication pattern of base station-relay station-terminal, wherein base station-relay station link is called as repeated link (backhaul link), relay station-terminal links is called as access link (access link), and base station-terminal links is called as the link that direct transfers (direct link).In multihop system, a part of terminal is linked under relay station, by relay station, completes communication service.After introducing relay station; need to guarantee the backwards compatibility for terminal; before guaranteeing, the terminal of version is (such as LTERelease-8; be called for short Rel-8) also can be linked under relay station; at this time just need to, not affecting under the prerequisite of relay station subordinate terminal communication, mark off a part of resource to guarantee the communication between base station and relay station.

In LTE-A system, according to working band, divide, Relay has (inband) and outer (outband) two kinds of band in band.In band, Relay refers to that the descending reception of RN and the descending transmission of RN occur in identical frequency band; Be with outer Relay to refer to that the descending reception of RN and the descending transmission of RN occur in different frequency bands.Take and be with interior Relay as example, in LTE-A system, definite base station-relay station communication and relay station-terminal communication are carried out with time division way at present, concrete, in descending sub frame, marking off a part for base station-relay station communication, these subframes are called as relaying (Relay) subframe.Rel-8 terminal for relay station subordinate, Relay subframe is indicated as MBSFN (Multicast Broadcast Single FrequencyNetwork, Multicast Broadcast Single Frequency Network, be called for short MBSFN) subframe, thereby Rel-8 terminal can be skipped these subframes, when completing base station-relay station communication, guaranteed the backwards compatibility for Rel-8 terminal.In LTE-A system, the structure of Relay subframe as shown in Figure 2.

In LTE-A system, the mode that downlink data transmission can be by space division multiplexing is to improve power system capacity.Under space division multiplexing transmission mode, be the equal of the data of a plurality of layers of multiplexing transmission (layer) on identical running time-frequency resource, the data of a plurality of layers were carried out the processing of precoding before mapping, to reach the object of eliminating interlayer interference.Concrete multiplexing number of layers is determined according to the order (rank) of MIMO (Multi-Input Multi-Output, multiple-input and multiple-output are called for short MIMO) channel.In current LTE-A system in the discussion of the descending link that direct transfers, a kind of pattern of the demodulated reference signal (demodulationreference signal, abbreviation DMRS) of supporting 4 layers of transmission as shown in Figure 3.Wherein, every two layers are divided into one group, between every group, adopt FDM (Frequency Division Multiplexing, frequency division multiplex, abbreviation FDM) mode keeps quadrature, in each group, adopts CDM (Code Division Multiplexing, code division multiplex, be called for short CDM) multiplexing two layers of mode, guarantee the DMRS quadrature of two layers.In Fig. 3, DMRS is positioned at the edge of a RB frequency domain, can guarantee that so single RB does the performance of channel estimating, with the density of time-frequency domain, can meet channel coherence bandwidth channel estimating performance hour.

For Relay in band, RN sends control information to subordinate terminal in front 1 or 2 OFDM symbol of Relay subframe, interval change-over time that process is switched from transmission state to accepting state afterwards, from base station, receive downlink data of relay link information, and then the conversion interval through switching from accepting state to transmission state.An exemplary plot as shown in Figure 4, owing to receiving-sending the conversion of state, causes last OFDM symbol of Relay subframe not receive, i.e. the resource structures of relay link downlink transmission can be different from the link that direct transfers.Therefore,, for repeated link, when last OFDM symbol is during for conversion interval from receptions-transmission state switching, repeated link is continued to use the DMRS pattern of the link that direct transfers, and will cause relay station not receive the DMRS on last symbol.

In the discussion of 3GPP LTE-A correlation technique, about the sending method of Relay downlink demodulation reference signals of relay link (Demodulation Reference Signal is called for short DMRS) and the discussion of associated problem, still fully do not launch at present.

Summary of the invention

In view of this, the technical problem to be solved in the present invention is to provide a kind of transmission method, base station, relay station and system of downlink demodulation reference signals of relay link, to solve the transmission problem of repeated link demodulated reference signal.

In order to address the above problem, the invention provides a kind of sending method of downlink demodulation reference signals of relay link, comprise: on the OFDM that downlink demodulation reference signals of relay link can receive at relay station (OFDM) symbol, send, described OFDM symbol does not comprise the OFDM symbol that is mapped with public reference signal.

Further, said method also can have following characteristics, and the time-domain position of described downlink demodulation reference signals of relay link in descending sub frame is:

When descending sub frame adopts general cyclic prefix, described downlink demodulation reference signals of relay link sends on the 6th, 7,13,14 OFDM symbols of described descending sub frame; Or described downlink demodulation reference signals of relay link sends on the 6th, 7,11,13 OFDM symbols of described descending sub frame; Or described downlink demodulation reference signals of relay link sends on the 6th, 7 OFDM symbols of described descending sub frame; Or described downlink demodulation reference signals of relay link sends on the 13rd, 14 OFDM symbols of described descending sub frame; Or described downlink demodulation reference signals of relay link sends on the 11st, 13 OFDM symbols of described descending sub frame.

Further, said method also can have following characteristics, and the time-domain position of described downlink demodulation reference signals of relay link in descending sub frame is:

When descending sub frame adopts extended cyclic prefix, described downlink demodulation reference signals of relay link sends on the 5th, 6,11,12 OFDM symbols of described descending sub frame; Or described downlink demodulation reference signals of relay link sends on the 5th, 6,9,11 OFDM symbols of described descending sub frame; Or described downlink demodulation reference signals of relay link sends on the 5th, 6 OFDM symbols of described descending sub frame; Or described downlink demodulation reference signals of relay link sends on the 11st, 12 OFDM symbols of described descending sub frame; Or described downlink demodulation reference signals of relay link sends on the 9th, 11 OFDM symbols of described descending sub frame.

Further, said method also can have following characteristics, and the frequency domain position of described downlink demodulation reference signals of relay link in Resource Block corresponding to descending sub frame is:

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 2nd, 7,12 or 1,6,11 subcarriers; During two-layer above transmission, described downlink demodulation reference signals of relay link sends on the 1st, 2,6,7,11,12 subcarriers.

Further, said method also can have following characteristics, and the time-frequency position of described downlink demodulation reference signals of relay link in Resource Block corresponding to descending sub frame is that described descending sub frame adopts extended cyclic prefix:

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 2nd, 5,8,11 subcarriers of the 5th and 6 OFDM symbols of described descending sub frame, on the 1st, 4,7,10 or 2,5,8,11 or 3,6,9,12 subcarriers of the 11st, 12 OFDM symbols, sends; During two-layer above transmission, described downlink demodulation reference signals of relay link sends on the 1st, 2,4,5,7,8,10,11 or 2,3,5,6,8,9,11,12 subcarriers of the 5th, 6 OFDM symbols of described descending sub frame, on the 1st, 2,4,5,7,8,10,11 or 2,3,5,6,8,9,11,12 subcarriers of the 11st, 12 OFDM symbols, sends;

Or,

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 2nd, 5,8,11 subcarriers of the 5th and 6 OFDM symbols of described descending sub frame, on the 1st, 4,7,10 or 3,6,9,12 or 2,5,8,11 subcarriers of the 9th, 11 OFDM symbols, sends; During two-layer above transmission, described downlink demodulation reference signals of relay link sends on the 1st, 2,4,5,7,8,10,11 or 2,3,5,6,8,9,11,12 subcarriers of the 5th, 6 OFDM symbols of described descending sub frame, on the 1st, 2,4,5,7,8,10,11 or 2,3,5,6,8,9,11,12 subcarriers of the 9th, 11 OFDM symbols, sends.

Further, said method also can have following characteristics, and the time-frequency position of described downlink demodulation reference signals of relay link in Resource Block corresponding to descending sub frame is that described descending sub frame adopts extended cyclic prefix:

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 2nd, 5,8,11 subcarriers of the 5th and 6 OFDM symbols of described descending sub frame; During two-layer above transmission, described downlink demodulation reference signals of relay link sends on the 1st, 2,4,5,7,8,10,11 or 2,3,5,6,8,9,11,12 subcarriers of the 5th, 6 OFDM symbols of described descending sub frame.

Further, said method also can have following characteristics, and the frequency domain position of described downlink demodulation reference signals of relay link in Resource Block corresponding to descending sub frame is:

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 2nd, 12 or 1,11 subcarriers; During two-layer above transmission, described downlink demodulation reference signals of relay link sends on the 1st, 2,11,12 subcarriers;

Or,

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 3rd, 9 or 4,10 subcarriers; During two-layer above transmission, described downlink demodulation reference signals of relay link sends on the 3rd, 4,9,10 subcarriers.

Further, said method also can have following characteristics, and when descending sub frame adopts general cyclic prefix, the time-domain position of described downlink demodulation reference signals of relay link in descending sub frame is:

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 7th, 13 or 6,13 OFDM symbols of described descending sub frame; During two-layer above transmission, described downlink demodulation reference signals of relay link on the 6th, 7,13,14 OFDM symbols of described descending sub frame, send or the 6th, 7,11,13 OFDM symbols on send.

Further, said method also can have following characteristics, and when descending sub frame adopts extended cyclic prefix, the time-domain position of described downlink demodulation reference signals of relay link in descending sub frame is:

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 6th, 11 OFDM symbols of described descending sub frame; During two-layer above transmission, described downlink demodulation reference signals of relay link on the 5th, 6,11,12 OFDM symbols of described descending sub frame, send or the 5th, 6,9,11 OFDM symbols on send.

Further, said method also can have following characteristics, and the frequency domain position of described downlink demodulation reference signals of relay link in Resource Block corresponding to descending sub frame is:

Described downlink demodulation reference signals of relay link sends on the 1st, 2,6,7,11,12 subcarriers.

Further, said method also can have following characteristics, and when descending sub frame adopts general cyclic prefix, the time-frequency position of described downlink demodulation reference signals of relay link in descending sub frame Resource Block is:

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 7th, 14 OFDM symbols of described descending sub frame or the 6th, 13 OFDM symbols; During two-layer above transmission, described downlink demodulation reference signals of relay link on the 6th, 7,13,14 OFDM symbols of described descending sub frame, send or the 6th, 7,11,13 OFDM symbols on send; Described downlink demodulation reference signals of relay link sends on the 1st, 2,11,12 subcarriers; Or described downlink demodulation reference signals of relay link sends on the 3rd, 4,9,10 subcarriers.

Further, said method also can have following characteristics, and described downlink demodulation reference signals of relay link is only mapped in the Resource Block and transport layer that repeated link transfer of data dispatches.

Further, said method also can have following characteristics, described downlink demodulation reference signals of relay link is that relay station is specific, and the downlink demodulation reference signals of relay link that is transferred to a given trunk station is carried out identical pre-encode operation with downlink data of relay link.

Further, said method also can have following characteristics, when described downlink demodulation reference signals of relay link multilayer transmission, the downlink demodulation reference signals of relay link of each transport layer adopts the mode of one or several combinations in code division multiplex, frequency division multiplex, time division multiplexing to keep quadrature.

The present invention also provides a kind of sending method of downlink demodulation reference signals of relay link, comprise: when descending sub frame adopts general cyclic prefix, base station sends downlink demodulation reference signals of relay link on the 6th, 7,11,13 OFDM symbols of described descending sub frame; Or, on the 6th, 7 OFDM symbols of described descending sub frame, send downlink demodulation reference signals of relay link; Or, on the 13rd, 14 OFDM symbols of described descending sub frame, send downlink demodulation reference signals of relay link; Or, on the 11st, 13 OFDM symbols of described descending sub frame, send downlink demodulation reference signals of relay link.

Further, said method also can have following characteristics, and the frequency domain position of described downlink demodulation reference signals of relay link in Resource Block corresponding to descending sub frame is:

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 2nd, 7,12 or 1,6,11 subcarriers; During two-layer above transmission, described downlink demodulation reference signals of relay link sends on the 1st, 2,6,7,11,12 subcarriers.

Further, said method also can have following characteristics, and the frequency domain position of described downlink demodulation reference signals of relay link in Resource Block corresponding to descending sub frame is:

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 2nd, 12 or 1,11 subcarriers; During two-layer above transmission, described downlink demodulation reference signals of relay link sends on the 1st, 2,11,12 subcarriers;

Or,

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 3rd, 9 or 4,10 subcarriers; During two-layer above transmission, described downlink demodulation reference signals of relay link sends on the 3rd, 4,9,10 subcarriers.

Further, said method also can have following characteristics, and described downlink demodulation reference signals of relay link is only mapped in the Resource Block and transport layer that repeated link transfer of data dispatches.

Further, said method also can have following characteristics, described downlink demodulation reference signals of relay link is that relay station is specific, and the downlink demodulation reference signals of relay link that is transferred to a given trunk station is carried out identical pre-encode operation with downlink data of relay link.

Further, said method also can have following characteristics, when described downlink demodulation reference signals of relay link multilayer transmission, the downlink demodulation reference signals of relay link of each transport layer adopts the mode of one or several combinations in code division multiplex, frequency division multiplex, time division multiplexing to keep quadrature.

The present invention also provides a kind of sending method of downlink demodulation reference signals of relay link, comprising: when descending sub frame adopts extended cyclic prefix, base station sends downlink demodulation reference signals of relay link on the 5th, 6,9,11 OFDM symbols of described descending sub frame; Or, on the 5th, 6 OFDM symbols of described descending sub frame, send downlink demodulation reference signals of relay link; Or, on the 11st, 12 OFDM symbols of described descending sub frame, send described downlink demodulation reference signals of relay link; Or, on the 9th, 11 OFDM symbols of described descending sub frame, send described downlink demodulation reference signals of relay link.

Further, said method also can have following characteristics, and the frequency domain position of described downlink demodulation reference signals of relay link in Resource Block corresponding to descending sub frame is:

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 2nd, 7,12 or 1,6,11 subcarriers; During two-layer above transmission, described downlink demodulation reference signals of relay link sends on the 1st, 2,6,7,11,12 subcarriers.

Further, said method also can have following characteristics, and the frequency domain position of described downlink demodulation reference signals of relay link in Resource Block corresponding to descending sub frame is:

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 2nd, 5,8,11 subcarriers; During two-layer above transmission, described downlink demodulation reference signals of relay link sends on the 1st, 2,4,5,7,8,10,11 or 2,3,5,6,8,9,11,12 subcarriers.

Further, said method also can have following characteristics, base station sends downlink demodulation reference signals of relay link on the 5th, 6,9,11 OFDM symbols of described descending sub frame, and the frequency domain position of described downlink demodulation reference signals of relay link in Resource Block corresponding to descending sub frame is:

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 2nd, 5,8,11 subcarriers of the 5th and 6 OFDM symbols of described descending sub frame, on the 1st, 4,7,10 or 3,6,9,12 or 2,5,8,11 subcarriers of the 9th, 11 OFDM symbols, sends; During two-layer above transmission, described downlink demodulation reference signals of relay link sends on the 1st, 2,4,5,7,8,10,11 or 2,3,5,6,8,9,11,12 subcarriers of the 5th, 6 OFDM symbols of described descending sub frame, on the 1st, 2,4,5,7,8,10,11 or 2,3,5,6,8,9,11,12 subcarriers of the 9th, 11 OFDM symbols, sends.

Further, said method also can have following characteristics, and described downlink demodulation reference signals of relay link is only mapped in the Resource Block and transport layer that repeated link transfer of data dispatches.

Further, said method also can have following characteristics, described downlink demodulation reference signals of relay link is that relay station is specific, and the downlink demodulation reference signals of relay link that is transferred to a given trunk station is carried out identical pre-encode operation with downlink data of relay link.

Further, said method also can have following characteristics, when described downlink demodulation reference signals of relay link multilayer transmission, the downlink demodulation reference signals of relay link of each transport layer adopts the mode of one or several combinations in code division multiplex, frequency division multiplex, time division multiplexing to keep quadrature.

The present invention also provides ，Gai base station, a kind of base station to comprise:

Memory module, for storing the pattern of the downlink demodulation reference signals of relay link from base-station transmission;

Sending module, is connected to memory module, for sending corresponding downlink demodulation reference signals of relay link according to the number of layers of downlink demodulation reference signals of relay link transmission and corresponding downlink demodulation reference signals of relay link pattern; In the OFDM symbol that described downlink demodulation reference signals of relay link only can receive at relay station, send, described OFDM symbol does not comprise the OFDM symbol that is mapped with public reference signal.

The present invention also provides a kind of relay station, this relay station comprises receiver module, be used for receiving downlink demodulation reference signals of relay link, in the OFDM symbol that described downlink demodulation reference signals of relay link only can receive at relay station, send, described OFDM symbol does not comprise the OFDM symbol that is mapped with public reference signal.

The present invention also provides a kind of relay system, comprises base station and relay station, wherein:

Described base station comprises:

Memory module, for storing the pattern of the downlink demodulation reference signals of relay link from base-station transmission;

Sending module, is connected to memory module, for sending corresponding downlink demodulation reference signals of relay link according to the number of layers of downlink demodulation reference signals of relay link transmission and corresponding downlink demodulation reference signals of relay link pattern;

Described relay station comprises:

Receiver module, for receiving described downlink demodulation reference signals of relay link;

Wherein, in the OFDM symbol that described downlink demodulation reference signals of relay link only can receive at relay station, send, described OFDM symbol does not comprise the OFDM symbol that is mapped with public reference signal.

By sending method and base station, relay station and the system of repeated link demodulated reference signal of the present invention, solved the transmission problem of downlink demodulation reference signals of relay link, guaranteed that relay station receives the reliability of downlink demodulation reference signals of relay link, guaranteed that downlink demodulation reference signals of relay link has a rational distribution density in Resource Block simultaneously, thereby guaranteed the reliability of downlink data of relay link transmission.And when repeated link exists CRS when (Cell-specific Reference Signal, public reference signal are called for short CRS), the demodulated reference signal that the present invention describes can not disturb with CRS, has avoided the impact on terminal.

Accompanying drawing explanation

Accompanying drawing described herein is used to provide a further understanding of the present invention, forms the application's a part, and schematic description and description of the present invention is used for explaining the present invention, does not form inappropriate limitation of the present invention.In the accompanying drawings:

Fig. 1 is the frame structure schematic diagram of LTE/LTE-A system;

Fig. 2 is descending Relay subframe structure schematic diagram;

Fig. 3 is the subframe discussed in the LTE-A system demodulated reference signal pattern while having general cyclic prefix;

Fig. 4 is a schematic diagram of relay link downlink resource structures;

Fig. 5 is the demodulated reference signal pattern schematic diagram of the embodiment of the present invention 1;

Fig. 6 is the demodulated reference signal pattern schematic diagram of the embodiment of the present invention 1;

Fig. 7 is the demodulated reference signal pattern schematic diagram of the embodiment of the present invention 1;

Fig. 8 is the demodulated reference signal pattern schematic diagram of the embodiment of the present invention 2;

Fig. 9 is the demodulated reference signal pattern schematic diagram of the embodiment of the present invention 2;

Figure 10 is the demodulated reference signal pattern schematic diagram of the embodiment of the present invention 3;

Figure 11 is the demodulated reference signal pattern schematic diagram of the embodiment of the present invention 3;

Figure 12 is the demodulated reference signal pattern schematic diagram of the embodiment of the present invention 3;

Figure 13 is the demodulated reference signal pattern schematic diagram of the embodiment of the present invention 4;

Figure 14 is the demodulated reference signal pattern schematic diagram of the embodiment of the present invention 4;

Figure 15 is the demodulated reference signal pattern schematic diagram of the embodiment of the present invention 4;

Figure 16 is the demodulated reference signal pattern schematic diagram of the embodiment of the present invention 4;

Figure 17 is the demodulated reference signal pattern schematic diagram of the embodiment of the present invention 5;

Figure 18 is the demodulated reference signal pattern schematic diagram of the embodiment of the present invention 5;

Figure 19 is the demodulated reference signal pattern schematic diagram of the embodiment of the present invention 5;

Figure 20 is the demodulated reference signal pattern schematic diagram of the embodiment of the present invention 5;

Figure 21 is the demodulated reference signal pattern schematic diagram of the embodiment of the present invention 6;

Figure 22 is the demodulated reference signal pattern schematic diagram of the embodiment of the present invention 6;

Figure 23 is the demodulated reference signal pattern schematic diagram of the embodiment of the present invention 8;

Figure 24 is the demodulated reference signal pattern schematic diagram of the embodiment of the present invention 8;

Figure 25 is the demodulated reference signal pattern schematic diagram of the embodiment of the present invention 8;

Figure 26 is base station of the present invention embodiment schematic diagram.

Embodiment

In the discussion of current 3GPP LTE-A correlation technique, also do not relate to the relevant discussion of relay link downlink DMRS.Embodiments of the invention provide the sending method of a kind of relay link downlink DMRS.

The design of DMRS of the present invention with transmission principle is, in the OFDM symbol that relay link downlink DMRS only can receive at relay station, sends, and described OFDM symbol does not comprise the OFDM symbol that sends public reference signal CRS.Particularly:

When subframe is used common CP, DMRS preferably sends on the 6th, 7,13,14 OFDM symbols, or sends on the 6th, 7,11,13 OFDM symbols;

When subframe is used expansion CP, DMRS preferably sends on the 5th, 6,11,12 OFDM symbols, or sends on the 5th, 6,9,11 OFDM symbols.

Further, DMRS is only mapped in downlink data of relay link and transmits in the RB and transport layer dispatching, and carries out identical pre-encode operation with the data in described transport layer, and described DMRS is relay station specific (RN-specific).

When DMRS multilayer transmission, the DMRS of each layer is mutually orthogonal.The orthogonal manner of the DMRS of the multilayer of the present invention statement can be one or several the combination in FDM, TDM, CDM.

Subframe for downlink data of relay link transmission; if the protection interval that last OFDM symbol of this subframe switches as receive-transmission of relay station state; relay station will not receive this OFDM symbol so; at this time under common CP length; relay link downlink DMRS preferably sends on the 6th, 7,11,13 OFDM symbols; under expansion CP length, relay link downlink DMRS preferably sends on the 5th, 6,9,11 OFDM symbols.

The present invention also provides a kind of sending method of downlink demodulation reference signals of relay link, comprise: when descending sub frame adopts general cyclic prefix, base station sends downlink demodulation reference signals of relay link on the 6th, 7,11,13 OFDM symbols of described descending sub frame; Or, on the 6th, 7 OFDM symbols of described descending sub frame, send downlink demodulation reference signals of relay link; Or, on the 13rd, 14 OFDM symbols of described descending sub frame, send downlink demodulation reference signals of relay link; Or, on the 11st, 13 OFDM symbols of described descending sub frame, send downlink demodulation reference signals of relay link.

The present invention also provides a kind of sending method of downlink demodulation reference signals of relay link, comprising: when descending sub frame adopts extended cyclic prefix, base station sends downlink demodulation reference signals of relay link on the 5th, 6,9,11 OFDM symbols of described descending sub frame; Or, on the 5th, 6 OFDM symbols of described descending sub frame, send downlink demodulation reference signals of relay link; Or, on the 11st, 12 OFDM symbols of described descending sub frame, send described downlink demodulation reference signals of relay link; Or, on the 9th, 11 OFDM symbols of described descending sub frame, send described downlink demodulation reference signals of relay link.

By above method, solved the transmission problem of downlink demodulation reference signals of relay link, guaranteed that relay station receives the reliability of downlink demodulation reference signals of relay link, guaranteed that downlink demodulation reference signals of relay link has a rational distribution density in time domain simultaneously, thereby guaranteed the reliability of downlink data of relay link transmission.

Below in conjunction with specific embodiment, implementation procedure of the present invention is described in detail.

Embodiment 1:

In this example, the Specific Principles that repeated link DMRS sends is on the OFDM symbol that DMRS can receive at relay station, to send, and there is no CRS on this OFDM symbol.Concrete, DMRS is identical in direct transfer frequency domain density and the sub-carrier positions of DMRS of link of the density of frequency domain and the sub-carrier positions of mapping and LTE-A; In time domain, if do not cause the DMRS transmitting on a corresponding in the end OFDM symbol not receive because last OFDM symbol receives, adjust so the OFDM character position of the DMRS transmission not receiving.

When the subframe of relay transmission has common CP length, and when in subframe, last OFDM symbol relay station does not receive, the link DMRS that supposes to direct transfer adopts the DMRS pattern shown in Fig. 3, and a pattern example of the downlink demodulation reference signals of relay link that the present invention describes so as shown in Figure 5.Concrete, wherein, suppose in figure in a RB that subcarrier number is 1 to 12 (continuing to use this hypothesis in follow-up explanation) from the bottom up, the DMRS of repeated link transmits on the 6th, 7,11,13 OFDM symbols of described subframe, and frequency domain position can be on interior the 2nd, 7,12 or 1,6,11 subcarriers of RB (individual layer or double-deck DMRS transmission) or the 1st, 2,6,7,11,12 subcarriers (two-layer above DMRS transmission).

When the subframe of repeated link downlink transfer has expansion CP length, and when in subframe, last OFDM symbol relay station does not receive, a pattern example of the downlink demodulation reference signals of relay link that the present invention describes as shown in Figure 6.Concrete, the DMRS of repeated link transmits on the 5th, 6,9,11 OFDM symbols of current subframe, and frequency domain position can be on interior the 2nd, 7,12 or 1,6,11 subcarriers of RB (individual layer or double-deck DMRS transmission) or the 1st, 2,6,7,11,12 subcarriers (two-layer above DMRS transmission).

Spectrum-spreading unit of ellipse representation in Fig. 5 and Fig. 6.When different layers DMRS is mapped in same time-frequency resource, adopt the mode of CDM time domain spread spectrum to guarantee each layer of DMRS quadrature.Concrete spread spectrum mode and the selection of spreading code are identical with spread spectrum mode and the spreading code of the link DMRS that direct transfers.For example, when a spectrum-spreading unit has 2 RE, use the Walsh code that length is 2 to carry out orthogonal spectrum expansion, for example, get [1,1] and [1 ,-1]; When a spectrum-spreading unit has 4 RE, use the Walsh code that length is 4 to carry out orthogonal spectrum expansion, be for example taken as:

$\left\{\begin{array}{c}\left[\mathrm{1,1,1,1}\right]\\ [1,-\mathrm{1,1},-1]\\ [\mathrm{1,1},-1,-1]\\ [1,-1,-\mathrm{1,1}]\end{array}\right.$

When transport layer number is greater than 4, if subframe has common CP length, DMRS also can adopt pattern as shown in Figure 7.The DMRS pattern of expansion CP length can similarly obtain, and repeats no more here.

It should be noted that the CRS pattern that just schematically describes LTE system in this routine schematic diagram.If base station is used MBSFN subframe to transmit data to relay station, in the OFDM symbol after the 3rd OFDM symbol, can not there is not CRS.

Should be appreciated that the DMRS pattern in this example just plays description and explains object of the present invention, and also paired not restriction of the present invention.

Embodiment 2:

Under the hypothesis of embodiment 1, the example of a DMRS design under expansion CP length as shown in Figure 8.The time-frequency position of DMRS in RB is: on the 2nd, 5,8,11 subcarriers of the 5th, 6 OFDM symbols, the 1st, 4,7,10 or 3,6 of the 9th, 11 OFDM symbols, on 9,12 subcarriers (individual layer DMRS or double-deck DMRS transmission); Or, at the 1st, 2,4,5,7,8,10,11 or 2,3,5 of the 5th, 6 OFDM symbols, 6,8,9,11, on 12 subcarriers, the 2nd, 3,5,6,8 of the 9th, 11 OFDM symbols, 9,11,12 or 1,2,4,5,7,8, on 10,11 subcarriers (two-layer above DMRS transmission).

Pattern shown in Fig. 8 can guarantee hour have good channel estimating performance at channel coherence bandwidth.Here repeat no more.

It shown in Fig. 9, is the example of another one DMRS design under expansion CP length.The time-frequency position of DMRS in a RB is: on the 2nd, 5,8,11 subcarriers of the 5th, 6 OFDM symbols, on the 2nd, 5,8,11 subcarriers of the 9th, 11 OFDM symbols (individual layer DMRS or double-deck DMRS transmission); Or, at the 5th, 6 OFDM symbols the 1st, 2,4,5,7,8,10,11 or 2,3,5,6,8,9,11, on 12 subcarriers, the 9th, 11 OFDM symbols the 1st, 2,4,5,7,8,10,11 or 2,3,5,6,8,9, on 11,12 subcarriers (two-layer above DMRS transmission).

In this embodiment, the orthogonal spectrum expansion of different layers and embodiment 1 are similar, repeat no more here.

It should be noted that the CRS pattern that just schematically describes LTE system in this routine schematic diagram.If base station is used MBSFN subframe to transmit data to relay station, in the OFDM symbol after the 3rd OFDM symbol, can not there is not CRS.

Should be appreciated that the DMRS pattern in this example just plays description and explains object of the present invention, and also paired not restriction of the present invention.

Embodiment 3:

In this example, the Specific Principles that repeated link DMRS sends is on the OFDM symbol that DMRS can receive at relay station, to send, and there is no CRS on this OFDM symbol.Concrete, DMRS is identical in direct transfer frequency domain density and the sub-carrier positions of DMRS of link of the density of frequency domain and the sub-carrier positions of mapping and LTE-A; In time domain, if do not cause the DMRS being mapped in accordingly on last OFDM symbol not receive because last OFDM symbol receives, so directly the DMRS not receiving is destroyed.

When the subframe of relay transmission has common CP length, and when in subframe, last OFDM symbol relay station does not receive, the link DMRS that supposes to direct transfer adopts the DMRS pattern shown in Fig. 3.During due to multilayer transmission, need time domain spread spectrum with multiplexing different layers, if therefore the DMRS on the 14th OFDM symbol is destroyed, the DMRS on the 13rd OFDM symbol cannot be used equally when multilayer transmission, is also destroyed.A pattern example of the downlink demodulation reference signals of relay link that the present invention describes so as shown in figure 10.Concrete, the DMRS of repeated link transmits on the 6th, 7 OFDM symbols of current subframe, and frequency domain position can be on interior the 2nd, 7,12 or 1,6,11 subcarriers of a RB (individual layer or double-deck DMRS transmission) or the 1st, 2,6,7,11,12 subcarriers (two-layer above DMRS transmission).

When the subframe of relay transmission has expansion CP length, and when in subframe, last OFDM symbol relay station does not receive, a pattern example of the downlink demodulation reference signals of relay link that the present invention describes as shown in figure 11.Concrete, the DMRS of repeated link transmits on the 5th, 6 OFDM symbols of current subframe, and frequency domain position can be on interior the 2nd, 7,12 or 1,6,11 subcarriers of a RB (individual layer or double-deck DMRS transmission) or the 1st, 2,6,7,11,12 subcarriers (two-layer above DMRS transmission).

Under expansion CP length, when relay station does not receive in subframe last OFDM symbol, the another one pattern example of the downlink demodulation reference signals of relay link that the present invention describes as shown in figure 12.Concrete, the DMRS of repeated link transmits on the 5th, 6 OFDM symbols of current subframe, frequency domain position can be the 2nd, 5,8,11 subcarriers (individual layer or double-deck DMRS transmission) or the 1st, 2,4,5,7,8,10,11 or 2 in a RB, 3,5,6,8,9,11,12 subcarriers (two-layer above DMRS transmission) repeat no more here.

Figure 10,11 and Figure 12 in spectrum-spreading unit of ellipse representation.When different layers DMRS is mapped in identical time-frequency resource, adopt the mode of CDM time domain spread spectrum to guarantee each layer of DMRS quadrature.Concrete spread spectrum mode is identical with the link that direct transfers with the selection of spreading code.For example, when a spectrum-spreading unit has 2 RE, use the Walsh code that length is 2 to carry out spread spectrum, for example, get [1,1] and [1 ,-1]; When a spectrum-spreading unit has 4 RE, use the Walsh code that length is 4 to carry out spread spectrum, be for example taken as:

$\left\{\begin{array}{c}\left[\mathrm{1,1,1,1}\right]\\ [1,-\mathrm{1,1},-1]\\ [\mathrm{1,1},-1,-1]\\ [1,-1,-\mathrm{1,1}]\end{array}\right..$

It should be noted that the CRS pattern that just schematically describes LTE system in this routine schematic diagram.If base station is used MBSFN subframe to transmit data to relay station, in the OFDM symbol after the 3rd OFDM symbol, can not there is not CRS.

Should be appreciated that the DMRS pattern in this example just plays description and explains object of the present invention, and also paired not restriction of the present invention.

Embodiment 4:

Because the antenna of relay station is conventionally higher, the channel conditions of repeated link tends to be better than the link that direct transfers, and can on the basis of link DMRS frequency domain density that direct transfers, reduce the DMRS density of repeated link so.

Suppose to direct transfer link DMRS pattern as shown in Figure 3.So under this example hypothesis, if relay station can receive last OFDM symbol of subframe, under common CP length, the example of relay link downlink DMRS detail of design as shown in figure 13, DMRS transmits on the 6th, 7,13,14 OFDM symbols, and frequency domain position can be on the 2nd, 12 or 1,11 subcarriers (individual layer or double-deck DMRS transmission) or 1,2,11,12 subcarrier (two-layer above DMRS transmission) in a RB.

If last OFDM symbol relay station does not receive, DMRS is adjusted into the 6th, 7,11,13 OFDM symbols at the OFDM symbol of time domain transmission so, the 2nd, 12 or 1,11 subcarriers (individual layer or double-deck DMRS transmission) or 1,2,11,12 subcarrier (two-layer above DMRS transmission) that frequency domain position can be in a RB are upper, repeat no more here.

If last OFDM symbol relay station does not receive, also the DMRS on the 13rd, 14 OFDM symbols can be destroyed, the DMRS that at this time the present invention describes only transmits on the 6th, 7 OFDM symbols, the 2nd, 12 or 1,11 subcarriers (individual layer or double-deck DMRS transmission) or 1,2,11,12 subcarrier (two-layer above DMRS transmission) that frequency domain position can be in a RB are upper, as shown in figure 14.Here repeat no more.

Under the hypothesis of this example, the example of another one relay link downlink DMRS design as shown in figure 15, DMRS transmits on the 6th, 7,13,14 OFDM symbols, and frequency domain position can be on interior the 4th, 10 or 3,9 subcarriers of a RB (individual layer or double-deck DMRS transmission) or the 3rd, 4,9,10 subcarriers (two-layer above DMRS transmission).If last OFDM symbol does not receive, the OFDM symbol of DMRS transmission is adjusted into the 6th, 7,11,13 OFDM symbols so, and frequency domain position can be on interior the 4th, 10 or 3,9 subcarriers of a RB (individual layer or double-deck DMRS transmission) or 3,4,9,10 subcarriers (two-layer above DMRS transmission).

If last OFDM symbol relay station does not receive, for the DMRS pattern shown in Figure 15, also the DMRS on the 13rd, 14 OFDM symbols can be destroyed, the DMRS that at this time the present invention describes only transmits on the 6th, 7 OFDM symbols, as shown in figure 16, frequency domain position can be interior the 4th, 10 or 3,9 subcarriers of a RB (individual layer or double-deck DMRS transmission) or the 3rd, 4,9,10 subcarriers (two-layer above DMRS transmission) are upper, repeats no more here.

Spectrum-spreading unit of ellipse representation in each schematic diagram of the present embodiment.When different layers DMRS is mapped in identical time-frequency resource, adopt the mode of CDM time domain spread spectrum to guarantee each layer of DMRS quadrature.Concrete spread spectrum mode is identical with the link that direct transfers with the selection of spreading code.For example, when a spectrum-spreading unit has 2 RE, use the Walsh code that length is 2 to carry out orthogonal spectrum expansion, for example, get [1,1] and [1 ,-1]; When a spectrum-spreading unit has 4 RE, use the Walsh code that length is 4 to carry out spread spectrum, be for example taken as:

$\left\{\begin{array}{c}\left[\mathrm{1,1,1,1}\right]\\ [1,-\mathrm{1,1},-1]\\ [\mathrm{1,1},-1,-1]\\ [1,-1,-\mathrm{1,1}]\end{array}\right..$

It should be noted that the CRS pattern that just schematically describes LTE system in this routine schematic diagram.If base station is used MBSFN subframe to transmit data to relay station, in the OFDM symbol after the 3rd OFDM symbol, can not there is not CRS.

Should be appreciated that the DMRS pattern in this example just plays description and explains object of the present invention, and also paired not restriction of the present invention.

Embodiment 5:

In this example, the Specific Principles that repeated link DMRS sends is on the OFDM symbol that DMRS can receive at relay station, to send, and there is no CRS on this OFDM symbol.

Concrete, under common CP length, DMRS during individual layer transmission sends on the 7th and the 13rd OFDM symbol, DMRS pattern when DMRS transmits with individual layer during two-layer transmission is identical, just adopt the mode of CDM frequency domain spread spectrum to guarantee two-layer DMRS quadrature, the spread spectrum is here two RE spread spectrums that DMRS pattern frequency domain is adjacent.As shown in figure 17, frequency domain position is on interior the 1st, 2,6,7,11,12 subcarriers of a RB to the pattern example that when individual layer and two-layer transmission, under common CP length, DMRS designs.Spectrum-spreading unit of ellipse representation in figure.

Under expansion CP length, DMRS design principle is identical with common CP length, be DMRS the 6th and 11 OFDM symbols on send.As shown in figure 18, frequency domain position is on interior the 1st, 2,6,7,11,12 subcarriers of a RB to DMRS pattern example when individual layer and two-layer transmission.

If relay station does not receive last OFDM symbol of downlink data of relay link transmission subframe, as shown in figure 19, DMRS uploads defeated at the 1st, 2,6,7,11,12 subcarriers of the 6th, 7,11,13 OFDM symbols a DMRS pattern example of lower four layers and the eight layers transmission of common CP length.The pattern of four layers of transmission is on the basis of two-layer transmission pattern, increases two-layer DMRS pattern and sends on the 6th and the 11st OFDM symbol, and the orthogonal manner of the two-layer DMRS pattern of increase is identical with the orthogonal manner in two-layer when transmission.As shown in figure 20, DMRS uploads defeated at the 1st, 2,6,7,11,12 subcarriers of the 5th, 6,9,11 OFDM symbols a DMRS pattern example of lower four layers and the eight layers transmission of expansion CP length.Here repeat no more.

Spectrum-spreading unit of ellipse representation in Figure 17,18,19,20.When different layers DMRS when identical-while frequently sending in resource, adopt the mode of CDM spread spectrum to guarantee each layer of DMRS quadrature.Concrete spread spectrum mode is that a RE in spectrum-spreading unit carries out orthogonal spectrum expansion, and the selection of spreading code is identical with the spreading code of the link DMRS that direct transfers.For example, when a spectrum-spreading unit has 2 RE, use the Walsh code that length is 2 to carry out orthogonal spectrum expansion, for example, get [1,1] and [1 ,-1]; When a spectrum-spreading unit has 4 RE, use the Walsh code that length is 4 to carry out orthogonal spectrum expansion, be for example taken as:

$\left\{\begin{array}{c}\left[\mathrm{1,1,1,1}\right]\\ [1,-\mathrm{1,1},-1]\\ [\mathrm{1,1},-1,-1]\\ [1,-1,-\mathrm{1,1}]\end{array}\right..$

It should be noted that the CRS pattern that just schematically describes LTE system in this routine schematic diagram.If base station is used MBSFN subframe to transmit data to relay station, in the OFDM symbol after the 3rd OFDM symbol, can not there is not CRS.

Should be appreciated that the DMRS pattern in this example just plays description and explains object of the present invention, and also paired not restriction of the present invention.

Embodiment 6:

Because the antenna of relay station is conventionally higher, the channel conditions of repeated link tends to be better than the link that direct transfers.Can, under the DMRS of embodiment 5 design principle, reduce the DMRS density of repeated link so.

Under this example hypothesis, if relay station can receive last OFDM symbol of subframe, under common CP length, the example of relay link downlink DMRS detail of design as shown in figure 21.When individual layer and two-layer DMRS transmission, DMRS sends on the 7th, 14 (or 6,13) individual OFDM symbol; During two-layer above DMRS transmission, DMRS sends on the 6th, 7,13,14 OFDM symbols, and frequency domain position is on interior the 1st, 2,11,12 subcarriers of a RB.

If last OFDM symbol relay station does not receive, DMRS is adjusted into the 6th, 7,11,13 OFDM symbols at the OFDM symbol of time domain mapping so, repeats no more here.

If last OFDM symbol relay station does not receive, also can limit base station to the number of layers of relay station transmission, can be restricted to maximum two layers of transmission, at this time only use the DMRS sending shown in Figure 21 during repeated link transfer of data on the 6th and the 13rd OFDM symbol.Here repeat no more.

Under the hypothesis of this example, the example of another one relay link downlink DMRS design as shown in figure 22.If last OFDM symbol does not receive, the OFDM symbol of DMRS mapping is adjusted into the 6th, 7,11,13 OFDM symbols so.

If last OFDM symbol relay station does not receive, also can limit base station to the number of layers of relay station transmission, can be restricted to maximum two layers of transmission, at this time only use the DMRS sending shown in Figure 22 during repeated link transfer of data on the 6th and the 13rd OFDM symbol.Here repeat no more.

Spectrum-spreading unit of ellipse representation in this example schematic.When different layers DMRS is mapped in identical time-frequency resource, adopt the mode of CDM to guarantee each layer of DMRS quadrature.Concrete spread spectrum mode is that a RE in spectrum-spreading unit carries out orthogonal spectrum expansion, and the selection of spreading code is identical with the link that direct transfers.For example, when a spectrum-spreading unit has 2 RE, use the Walsh code that length is 2 to carry out orthogonal spectrum expansion, for example, get [1,1] and [1 ,-1]; When a spectrum-spreading unit has 4 RE, use the Walsh code that length is 4 to carry out spread spectrum, be for example taken as:

$\left\{\begin{array}{c}\left[\mathrm{1,1,1,1}\right]\\ [1,-\mathrm{1,1},-1]\\ [\mathrm{1,1},-1,-1]\\ [1,-1,-\mathrm{1,1}]\end{array}\right..$

It should be noted that the CRS pattern that just schematically describes LTE system in this routine schematic diagram.If base station is used MBSFN subframe to transmit data to relay station, in the OFDM symbol after the 3rd OFDM symbol, can not there is not CRS.

Should be appreciated that the DMRS pattern in this example just plays description and explains object of the present invention, and also paired not restriction of the present invention.

Embodiment 7:

In TDD (Time Division Duplex, time division duplex are called for short TDD) LTE-A system, if be supported in special subframe S to relay station transmission trunking link downlink data, under common CP length, can adopt Figure 10, or Figure 14, or the DMRS pattern shown in Figure 16; Under expansion CP length, can adopt the DMRS pattern shown in Figure 11 or Figure 12.Identical in multiplexing and spread spectrum mode and the previous examples of different layers DMRS, repeats no more here.

Embodiment 8:

In this example, the Specific Principles that repeated link DMRS sends is on the OFDM symbol that DMRS can receive at relay station, to send, and there is no CRS on this OFDM symbol.

Concrete, under common CP length, if last OFDM symbol relay station can receive in subframe, the DMRS in individual layer when transmission the 13rd and 14 OFDM symbols on send, DMRS pattern when DMRS transmits with individual layer during two-layer transmission is identical, just adopt the mode of CDM time domain spread spectrum to guarantee two-layer DMRS quadrature, the spread spectrum is here two adjacent RE spread spectrums of time domain in DMRS pattern.A pattern example of the downlink demodulation reference signals of relay link that the present invention describes as shown in figure 23.Concrete, the DMRS of repeated link transmits on the 13rd, 14 OFDM symbols of subframe, and frequency domain position can be the 2nd, 7,12 or 1,6,11 subcarriers (individual layer or double-deck DMRS transmission) or the 1st, 2,6,7,11,12 subcarriers (two-layer above DMRS transmission) in a RB.

Under expansion CP length, DMRS design principle is identical with common CP length, be DMRS the 11st and 12 OFDM symbols on send.A pattern example of the downlink demodulation reference signals of relay link that the present invention describes as shown in figure 24.Concrete, the DMRS of repeated link transmits on the 11st, 12 OFDM symbols of subframe, and frequency domain position can be on interior the 2nd, 7,12 or 1,6,11 subcarriers of a RB (individual layer or double-deck DMRS transmission) or the 1st, 2,6,7,11,12 subcarriers (two-layer above DMRS transmission).

When in subframe, last OFDM symbol relay station does not receive, if subframe has common CP length, repeated link demodulated reference signal can send on the 11st, 13 OFDM symbols; If subframe has expansion CP length, repeated link demodulated reference signal can send on the 9th, 11 OFDM symbols, and frequency domain position as hereinbefore, repeats no more here.

Under expansion CP length, the another one pattern example of the downlink demodulation reference signals of relay link that the present invention describes as shown in figure 25.Concrete, the DMRS of repeated link transmits on the 11st, 12 OFDM symbols of subframe, frequency domain position can be the 2nd, 5,8,11 subcarriers (individual layer or double-deck DMRS transmission) or the 1st, 2,4,5,7,8,10,11 or 2 in a RB, 3,5,6,8,9,11,12 subcarriers (two-layer above DMRS transmission).If last OFDM symbol relay station does not receive in subframe, repeated link demodulated reference signal can send on the 9th, 11 OFDM symbols, and frequency domain position is constant, repeats no more here.

Figure 23,24 and Figure 25 in spectrum-spreading unit of ellipse representation.When different layers DMRS is mapped in same time-frequency resource, adopt the mode of CDM time domain spread spectrum to guarantee each layer of DMRS quadrature.Concrete spread spectrum mode and the selection of spreading code are identical with spread spectrum mode and the spreading code of the link DMRS that direct transfers.For example, when a spectrum-spreading unit has 2 RE, use the Walsh code that length is 2 to carry out orthogonal spectrum expansion, for example, get [1,1] and [1 ,-1].

It should be noted that the CRS pattern that just schematically describes LTE system in this routine schematic diagram.If base station is used MBSFN subframe to transmit data to relay station, in the OFDM symbol after the 3rd OFDM symbol, can not there is not CRS.

Should be appreciated that the DMRS pattern in this example just plays description and explains object of the present invention, and also paired not restriction of the present invention.

Device embodiment

According to embodiments of the invention, provide the ，Gai base station, a kind of base station can be for the transmission of downlink demodulation reference signals of relay link.

Figure 26 is according to the structured flowchart of the base station of the embodiment of the present invention, and as shown in figure 26, this base station comprises memory module 2610 and sending module 2620, wherein:

Memory module 2610, for storing the pattern of the downlink demodulation reference signals of relay link from base-station transmission;

Sending module 2620, is connected to memory module 2610, for sending corresponding downlink demodulation reference signals of relay link according to the number of layers of demodulated reference signal transmission and corresponding downlink demodulation reference signals of relay link pattern.

In the OFDM symbol that downlink demodulation reference signals of relay link described herein only can receive at relay station, send, described OFDM symbol does not comprise the OFDM symbol that is mapped with public reference signal, this demodulated reference signal is mapped in the Resource Block and transport layer that repeated link transfer of data dispatches, for the coherent demodulation of downlink data of relay link transmission.

According to embodiments of the invention, a kind of relay station is provided, this relay station is for the processing of downlink demodulation reference signals of relay link.

This relay station comprises receiver module, for receiving downlink demodulation reference signals of relay link.In the OFDM symbol that described downlink demodulation reference signals of relay link only can receive at relay station, send, described OFDM symbol does not comprise the OFDM symbol that is mapped with public reference signal, this downlink demodulation reference signals of relay link is mapped in the Resource Block and transport layer that repeated link transfer of data dispatches, for the coherent demodulation of downlink data of relay link transmission.

System embodiment

According to embodiments of the invention, a kind of relay system is provided, this relay system can be for the transmission of downlink demodulation reference signals of relay link.

This relay system comprises base station and relay station, and wherein, the structure of base station and relay station is identical with the structure of describing in above-mentioned device embodiment, and its concrete function and implementation procedure have been described in detail in device embodiment, repeat no more here.

In sum, by method of the present invention and base station and relay station, solved the transmission problem of repeated link demodulated reference signal, guaranteed that relay station receives the reliability of downlink demodulation reference signals of relay link, guaranteed that downlink demodulation reference signals of relay link has a rational distribution density simultaneously, thereby guaranteed the reliability of downlink data of relay link transmission, and can the terminal in same community not exerted an influence.

Obviously, those skilled in the art should be understood that, above-mentioned each module of the present invention or each step can realize with general calculation element, they can concentrate on single calculation element, or be distributed on the network that a plurality of calculation elements form, alternatively, they can be realized with the executable program code of calculation element, thereby, they can be stored in storage device and be carried out by calculation element, or they are made into respectively to each integrated circuit modules, or a plurality of modules in them or step are made into single integrated circuit module to be realized.Like this, the present invention is not restricted to any specific hardware and software combination.

The foregoing is only the preferred embodiments of the present invention, be not limited to the present invention, for a person skilled in the art, the present invention can have various modifications and variations.Within the spirit and principles in the present invention all, any modification of doing, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.

Claims (29)

1. the sending method of a downlink demodulation reference signals of relay link, it is characterized in that, comprise: on the orthogonal frequency division multiplex OFDM symbol that downlink demodulation reference signals of relay link can receive at relay station, send, described OFDM symbol does not comprise the OFDM symbol that is mapped with public reference signal; Wherein, described downlink demodulation reference signals of relay link is only mapped in the Resource Block and transport layer that repeated link transfer of data dispatches, and carries out identical pre-encode operation with the data in described transport layer.

2. the method for claim 1, is characterized in that,

The time-domain position of described downlink demodulation reference signals of relay link in descending sub frame is:

When descending sub frame adopts general cyclic prefix, described downlink demodulation reference signals of relay link sends on the 6th, 7,13,14 OFDM symbols of described descending sub frame; Or described downlink demodulation reference signals of relay link sends on the 6th, 7,11,13 OFDM symbols of described descending sub frame; Or described downlink demodulation reference signals of relay link sends on the 6th, 7 OFDM symbols of described descending sub frame; Or described downlink demodulation reference signals of relay link sends on the 13rd, 14 OFDM symbols of described descending sub frame; Or described downlink demodulation reference signals of relay link sends on the 11st, 13 OFDM symbols of described descending sub frame.

3. the method for claim 1, is characterized in that,

The time-domain position of described downlink demodulation reference signals of relay link in descending sub frame is:

When descending sub frame adopts extended cyclic prefix, described downlink demodulation reference signals of relay link sends on the 5th, 6,11,12 OFDM symbols of described descending sub frame; Or described downlink demodulation reference signals of relay link sends on the 5th, 6,9,11 OFDM symbols of described descending sub frame; Or described downlink demodulation reference signals of relay link sends on the 5th, 6 OFDM symbols of described descending sub frame; Or described downlink demodulation reference signals of relay link sends on the 11st, 12 OFDM symbols of described descending sub frame; Or described downlink demodulation reference signals of relay link sends on the 9th, 11 OFDM symbols of described descending sub frame.

4. method as claimed in claim 2 or claim 3, is characterized in that,

The frequency domain position of described downlink demodulation reference signals of relay link in Resource Block corresponding to descending sub frame is:

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 2nd, 7,12 or 1,6,11 subcarriers; During two-layer above transmission, described downlink demodulation reference signals of relay link sends on the 1st, 2,6,7,11,12 subcarriers.

5. the method for claim 1, is characterized in that,

The time-frequency position of described downlink demodulation reference signals of relay link in Resource Block corresponding to descending sub frame is that described descending sub frame adopts extended cyclic prefix:

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 2nd, 5,8,11 subcarriers of the 5th and 6 OFDM symbols of described descending sub frame, on the 1st, 4,7,10 or 2,5,8,11 or 3,6,9,12 subcarriers of the 11st, 12 OFDM symbols, sends; During two-layer above transmission, described downlink demodulation reference signals of relay link sends on the 1st, 2,4,5,7,8,10,11 or 2,3,5,6,8,9,11,12 subcarriers of the 5th, 6 OFDM symbols of described descending sub frame, on the 1st, 2,4,5,7,8,10,11 or 2,3,5,6,8,9,11,12 subcarriers of the 11st, 12 OFDM symbols, sends;

Or,

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 2nd, 5,8,11 subcarriers of the 5th and 6 OFDM symbols of described descending sub frame, on the 1st, 4,7,10 or 3,6,9,12 or 2,5,8,11 subcarriers of the 9th, 11 OFDM symbols, sends; During two-layer above transmission, described downlink demodulation reference signals of relay link sends on the 1st, 2,4,5,7,8,10,11 or 2,3,5,6,8,9,11,12 subcarriers of the 5th, 6 OFDM symbols of described descending sub frame, on the 1st, 2,4,5,7,8,10,11 or 2,3,5,6,8,9,11,12 subcarriers of the 9th, 11 OFDM symbols, sends.

6. the method for claim 1, is characterized in that,

The time-frequency position of described downlink demodulation reference signals of relay link in Resource Block corresponding to descending sub frame is that described descending sub frame adopts extended cyclic prefix:

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 2nd, 5,8,11 subcarriers of the 5th and 6 OFDM symbols of described descending sub frame; During two-layer above transmission, described downlink demodulation reference signals of relay link sends on the 1st, 2,4,5,7,8,10,11 or 2,3,5,6,8,9,11,12 subcarriers of the 5th, 6 OFDM symbols of described descending sub frame.

7. method as claimed in claim 2, is characterized in that,

The frequency domain position of described downlink demodulation reference signals of relay link in Resource Block corresponding to descending sub frame is:

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 2nd, 12 or 1,11 subcarriers; During two-layer above transmission, described downlink demodulation reference signals of relay link sends on the 1st, 2,11,12 subcarriers;

Or,

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 3rd, 9 or 4,10 subcarriers; During two-layer above transmission, described downlink demodulation reference signals of relay link sends on the 3rd, 4,9,10 subcarriers.

8. the method for claim 1, is characterized in that,

When descending sub frame adopts general cyclic prefix, the time-domain position of described downlink demodulation reference signals of relay link in descending sub frame is:

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 7th, 13 or 6,13 OFDM symbols of described descending sub frame; During two-layer above transmission, described downlink demodulation reference signals of relay link on the 6th, 7,13,14 OFDM symbols of described descending sub frame, send or the 6th, 7,11,13 OFDM symbols on send.

9. the method for claim 1, is characterized in that,

When descending sub frame adopts extended cyclic prefix, the time-domain position of described downlink demodulation reference signals of relay link in descending sub frame is:

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 6th, 11 OFDM symbols of described descending sub frame; During two-layer above transmission, described downlink demodulation reference signals of relay link on the 5th, 6,11,12 OFDM symbols of described descending sub frame, send or the 5th, 6,9,11 OFDM symbols on send.

10. method as claimed in claim 8 or 9, is characterized in that,

The frequency domain position of described downlink demodulation reference signals of relay link in Resource Block corresponding to descending sub frame is:

Described downlink demodulation reference signals of relay link sends on the 1st, 2,6,7,11,12 subcarriers.

11. the method for claim 1, is characterized in that,

When descending sub frame adopts general cyclic prefix, the time-frequency position of described downlink demodulation reference signals of relay link in descending sub frame Resource Block is:

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 7th, 14 OFDM symbols of described descending sub frame or the 6th, 13 OFDM symbols; During two-layer above transmission, described downlink demodulation reference signals of relay link on the 6th, 7,13,14 OFDM symbols of described descending sub frame, send or the 6th, 7,11,13 OFDM symbols on send; Described downlink demodulation reference signals of relay link sends on the 1st, 2,11,12 subcarriers; Or described downlink demodulation reference signals of relay link sends on the 3rd, 4,9,10 subcarriers.

12. methods as described in claim 1,2 or 3, is characterized in that,

Described downlink demodulation reference signals of relay link is that relay station is specific, and the downlink demodulation reference signals of relay link that is transferred to a given trunk station is carried out identical pre-encode operation with downlink data of relay link.

13. methods as described in claim 1,2 or 3, it is characterized in that, when described downlink demodulation reference signals of relay link multilayer transmission, the downlink demodulation reference signals of relay link of each transport layer adopts the mode of one or several combinations in code division multiplex, frequency division multiplex, time division multiplexing to keep quadrature.

The sending method of 14. 1 kinds of downlink demodulation reference signals of relay links, it is characterized in that, comprise: when descending sub frame adopts general cyclic prefix, base station sends downlink demodulation reference signals of relay link on the 6th, 7,11,13 OFDM symbols of described descending sub frame; Or, on the 6th, 7 OFDM symbols of described descending sub frame, send downlink demodulation reference signals of relay link; Or, on the 13rd, 14 OFDM symbols of described descending sub frame, send downlink demodulation reference signals of relay link; Or, on the 11st, 13 OFDM symbols of described descending sub frame, send downlink demodulation reference signals of relay link.

15. methods as claimed in claim 14, is characterized in that,

The frequency domain position of described downlink demodulation reference signals of relay link in Resource Block corresponding to descending sub frame is:

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 2nd, 7,12 or 1,6,11 subcarriers; During two-layer above transmission, described downlink demodulation reference signals of relay link sends on the 1st, 2,6,7,11,12 subcarriers.

16. methods as claimed in claim 14, is characterized in that,

The frequency domain position of described downlink demodulation reference signals of relay link in Resource Block corresponding to descending sub frame is:

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 2nd, 12 or 1,11 subcarriers; During two-layer above transmission, described downlink demodulation reference signals of relay link sends on the 1st, 2,11,12 subcarriers;

Or,

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 3rd, 9 or 4,10 subcarriers; During two-layer above transmission, described downlink demodulation reference signals of relay link sends on the 3rd, 4,9,10 subcarriers.

17. methods as claimed in claim 14, is characterized in that,

Described downlink demodulation reference signals of relay link is only mapped in the Resource Block and transport layer that repeated link transfer of data dispatches.

18. methods as claimed in claim 14, is characterized in that,

Described downlink demodulation reference signals of relay link is that relay station is specific, and the downlink demodulation reference signals of relay link that is transferred to a given trunk station is carried out identical pre-encode operation with downlink data of relay link.

19. methods as claimed in claim 14, it is characterized in that, when described downlink demodulation reference signals of relay link multilayer transmission, the downlink demodulation reference signals of relay link of each transport layer adopts the mode of one or several combinations in code division multiplex, frequency division multiplex, time division multiplexing to keep quadrature.

The sending method of 20. 1 kinds of downlink demodulation reference signals of relay links, it is characterized in that, comprise: when descending sub frame adopts extended cyclic prefix, base station sends downlink demodulation reference signals of relay link on the 5th, 6,9,11 OFDM symbols of described descending sub frame; Or, on the 5th, 6 OFDM symbols of described descending sub frame, send downlink demodulation reference signals of relay link; Or, on the 11st, 12 OFDM symbols of described descending sub frame, send described downlink demodulation reference signals of relay link; Or, on the 9th, 11 OFDM symbols of described descending sub frame, send described downlink demodulation reference signals of relay link.

21. methods as claimed in claim 20, is characterized in that,

The frequency domain position of described downlink demodulation reference signals of relay link in Resource Block corresponding to descending sub frame is:

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 2nd, 7,12 or 1,6,11 subcarriers; During two-layer above transmission, described downlink demodulation reference signals of relay link sends on the 1st, 2,6,7,11,12 subcarriers.

22. methods as claimed in claim 20, is characterized in that,

The frequency domain position of described downlink demodulation reference signals of relay link in Resource Block corresponding to descending sub frame is:

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 2nd, 5,8,11 subcarriers; During two-layer above transmission, described downlink demodulation reference signals of relay link sends on the 1st, 2,4,5,7,8,10,11 or 2,3,5,6,8,9,11,12 subcarriers.

23. methods as claimed in claim 20, is characterized in that,

Base station sends downlink demodulation reference signals of relay link on the 5th, 6,9,11 OFDM symbols of described descending sub frame, and the frequency domain position of described downlink demodulation reference signals of relay link in Resource Block corresponding to descending sub frame is:

When individual layer or two-layer transmission, described downlink demodulation reference signals of relay link sends on the 2nd, 5,8,11 subcarriers of the 5th and 6 OFDM symbols of described descending sub frame, on the 1st, 4,7,10 or 3,6,9,12 or 2,5,8,11 subcarriers of the 9th, 11 OFDM symbols, sends; During two-layer above transmission, described downlink demodulation reference signals of relay link sends on the 1st, 2,4,5,7,8,10,11 or 2,3,5,6,8,9,11,12 subcarriers of the 5th, 6 OFDM symbols of described descending sub frame, on the 1st, 2,4,5,7,8,10,11 or 2,3,5,6,8,9,11,12 subcarriers of the 9th, 11 OFDM symbols, sends.

24. methods as claimed in claim 20, is characterized in that,

Described downlink demodulation reference signals of relay link is only mapped in the Resource Block and transport layer that repeated link transfer of data dispatches.

25. methods as claimed in claim 20, is characterized in that,

Described downlink demodulation reference signals of relay link is that relay station is specific, and the downlink demodulation reference signals of relay link that is transferred to a given trunk station is carried out identical pre-encode operation with downlink data of relay link.

26. methods as claimed in claim 20, it is characterized in that, when described downlink demodulation reference signals of relay link multilayer transmission, the downlink demodulation reference signals of relay link of each transport layer adopts the mode of one or several combinations in code division multiplex, frequency division multiplex, time division multiplexing to keep quadrature.

27. 1 kinds of base stations, is characterized in that, this base station comprises:

Memory module, for storing the pattern of the downlink demodulation reference signals of relay link from base-station transmission;

Sending module, is connected to memory module, for sending corresponding downlink demodulation reference signals of relay link according to the number of layers of downlink demodulation reference signals of relay link transmission and corresponding downlink demodulation reference signals of relay link pattern; In the OFDM symbol that described downlink demodulation reference signals of relay link only can receive at relay station, send, described OFDM symbol does not comprise the OFDM symbol that is mapped with public reference signal.

28. 1 kinds of relay stations, it is characterized in that, this relay station comprises receiver module, be used for receiving downlink demodulation reference signals of relay link, in the OFDM symbol that described downlink demodulation reference signals of relay link only can receive at relay station, send, described OFDM symbol does not comprise the OFDM symbol that is mapped with public reference signal; Wherein, described downlink demodulation reference signals of relay link is only mapped in the Resource Block and transport layer that repeated link transfer of data dispatches, and carries out identical pre-encode operation with the data in described transport layer.

29. 1 kinds of relay systems, is characterized in that, comprise base station and relay station, wherein:

Described base station comprises:

Memory module, for storing the pattern of the downlink demodulation reference signals of relay link from base-station transmission;

Sending module, is connected to memory module, for sending corresponding downlink demodulation reference signals of relay link according to the number of layers of downlink demodulation reference signals of relay link transmission and corresponding downlink demodulation reference signals of relay link pattern;

Described relay station comprises:

Receiver module, for receiving described downlink demodulation reference signals of relay link;

Wherein, in the OFDM symbol that described downlink demodulation reference signals of relay link only can receive at relay station, send, described OFDM symbol does not comprise the OFDM symbol that is mapped with public reference signal.

Images