CN102088434B - Transmitting method of demodulation reference signal, sequence generating method and transmitting and receiving devices - Google Patents

Abstract

The invention relates to a transmitting method of a downlink link demodulation reference signal, transmitting and receiving devices and a generating method of a demodulation reference signal sequence. The transmitting method of the demodulation reference signal provided by the invention comprises the following step that: the transmitting device transmits the demodulation reference signal according to a demodulation reference signal pattern, wherein in the demodulation reference signal pattern, the receiving device can receive one or more orthogonal frequency division multiplexing (OFDM) symbols which are not occupied by a common reference signal (CRS) at the time domain position of the demodulation reference signal; and the demodulation reference signal is used for performing coherent demodulation on relay link downlink data transmission. Through the method and the devices, the transmission problem of a relay link downlink demodulation reference signal is solved and the conflict between the demodulation reference signal and the CRS is avoided.

Description

Demodulation reference signal sending method, sequence generation method, transmitting device and receiving device

Technical Field

The present invention relates to the field of mobile communications, and in particular, to a demodulation reference signal transmission method, a sequence generation method, and a transmitting and receiving apparatus.

Background

Currently, the development requirement of mobile communication is to support higher transmission rate, more perfect signal coverage and higher resource utilization. In order to achieve high transmission rate, the next generation mobile communication system will use a higher frequency bandwidth to transmit signals, and the higher frequency bandwidth will bring larger path loss at the same time, affecting network coverage. Relay (Relay) technology can increase coverage and balance and increase cell throughput, and Relay Nodes (RNs) have relatively smaller configuration cost than base stations, so Relay is regarded as a key technology in an LTE-Advanced (LTE-a) system, which is an evolved system of Long Term Evolution (Long Term Evolution, abbreviated as LTE).

The LTE/LTE-a system is based on OFDM (Orthogonal Frequency Division Multiplexing) technology. In an OFDM system, the communication resources are in the form of two dimensions, time-frequency. For example, in the LTE system, the communication resources of the downlink are divided in units of frames (frames) in the time direction, each radio frame (radio frame) has a length of 10ms, and includes 10 subframes (sub-frames) with a length of 1ms, as shown in fig. 1. Each subframe contains two slots (slots) in the time direction. Each subframe may include 14 or 12 OFDM symbols according to a CP (Cyclic Prefix, CP) length. When the sub-frame adopts the length of a common CP (normal CP), 14 OFDM symbols are contained in the sub-frame, and each time slot has 7 OFDM symbols; when the subframe adopts an extended cp (extended cp) length, the subframe includes 12 OFDM symbols, and each slot has 6 OFDM symbols. In the frequency direction, resources are divided in units of sub-carriers (sub-carriers), and specifically, in communication, the minimum unit of Resource allocation is an RB (Resource Block) and corresponds to one PRB (Physical RB) of a Physical Resource. One RB includes 12 subcarriers in the frequency domain, corresponding to 1 slot in the time domain, and two RBs adjacent in the time domain in the same subframe are called an RB pair (RB pair). The Resource corresponding to 1 subcarrier on each OFDM symbol is called a Resource Element (RE). A physical resource structure diagram under the normal CP length is shown in fig. 2.

After the introduction of the relay station, the communication mode of the original base station-terminal is changed into the communication mode of the base station-relay station-terminal, taking a two-hop system as an example, where the base station-relay station link is called a relay link (backhaul link), the relay station-terminal link is called an access link (access link), and the base station-terminal link is called a direct link (direct link). In the multi-hop system, a part of terminals are accessed to the relay station, and communication service is completed through the relay station. After the relay station is introduced, it is necessary to ensure backward compatibility with respect to the terminal, that is, it is necessary to ensure that a terminal of a previous version (such as lte early-8, Rel-8 for short) can also be accessed to the relay station, and at this time, it is necessary to partition a part of resources to ensure communication between the base station and the relay station on the premise of not affecting communication of terminals under the relay station. Currently, it is determined in the LTE-a system that the base station-Relay station communication and the Relay station-terminal communication are performed in a time division manner, and specifically, a part of the downlink subframe is divided for the base station-Relay station communication, and these subframes are called Relay (Relay) subframes. For a Rel-8 terminal under a Relay station, a Relay subframe is indicated as an MBSFN (Multicast Broadcast Single Frequency Network, MBSFN for short) subframe, so that the Rel-8 terminal can skip the subframes, and backward compatibility of the Rel-8 terminal is ensured while base station-Relay station communication is completed. In the LTE-a system, the structure of a Relay subframe is shown in fig. 3. In the Relay subframe shown in fig. 3, the Relay station transmits control information, i.e., a PDCCH (Physical downlink control Channel, PDCCH for short) to the subordinate terminal on the first 1 or 2 OFDM symbols. Then the relay station receives the downlink data information of the relay link from the base station through a protection time interval for switching from a sending state to a receiving state, and then passes through the protection time interval for switching from the receiving state to the sending state. That is, in the Relay subframe, the Relay station can receive only a part of OFDM symbols.

In the Relay subframe, the transmission of data will include Relay link downlink traffic information, Relay link control information, etc. Considering that the overhead of a common-reference signal (CRS) is relatively large, the LTE-a system supports downlink unicast service data transmission in an MBSFN subframe. In MBSFN subframes, CRS will only be transmitted on the first 1 or 2 OFDM symbols of the subframe. Specifically, according to the LTE Rel-8 protocol, when a subframe has a normal CP length, in a normal subframe (non-MBSFN subframe), a base station transmits CRS in 1 st, 5 th, 8 th, and 12 th OFDM symbols (CRS ports 0 and 1) and 2 nd and 9 th OFDM symbols (CRS ports 2 and 3); in MBSFN subframes, the base station transmits CRS only in the 1 st OFDM symbol (CRS ports 0, 1) and the 2 nd OFDM symbol (ports 2, 3). As shown in (1) and (2) in fig. 4, respectively, it is assumed here that the MBSFN subframe also has a normal CP length. For a relay station, relay link downlink traffic may also need to support transmission in MBSFN subframes. In both normal subframes (non-MBSFN subframes) and MBSFN subframes, reliable transmission of downlink data in a relay link needs to be supported by a corresponding demodulation reference Signal (DMRS).

The LTE/LTE-a system widely applies a MIMO (multiple-Input multiple-Output, MIMO for short) technology. In the MIMO system, the transmission of signals may be in a Transmit Diversity (Transmit Diversity) mode, a Beamforming (Beamforming) mode, a Spatial Multiplexing (Spatial Multiplexing) mode, or the like. The transmit diversity obtains diversity gain and coding gain through space-frequency (time-frequency) coding; the beam forming technology improves the system capacity and enlarges the coverage range by changing the beam shape; space division multiplexing techniques increase system capacity by transmitting data for multiple streams on the same time-frequency resource. In both beamforming and spatial multiplexing transmission modes, data is precoded (Precoding) before transmission. In different transmission modes, the demodulation reference signal may also be processed in different manners, for example, in beamforming and spatial multiplexing modes of the LTE-a system, the demodulation reference signal and corresponding data undergo the same precoding operation, but in transmit diversity mode, the demodulation reference signal is not processed. Meanwhile, the reference signals in the MIMO system generally need to support multi-antenna port/multi-layer transmission, the reference signals of different ports or transmission layers are multiplexed in the time-frequency resource, and the demodulation reference signals of each port/layer are orthogonal to each other.

At present, in the discussion of the 3GPP LTE-a related technology, the detailed discussion about the transmission method of the relay link downlink demodulation reference signal and the problems related thereto is still not fully developed.

Disclosure of Invention

The technical problem to be solved by the present invention is to provide a method, a transmitter, and a receiver for transmitting a downlink demodulation reference signal, so as to solve the transmission problem of the downlink demodulation reference signal in a relay link and avoid the collision between the demodulation reference signal and a common reference signal CRS.

In order to solve the above technical problem, the present invention provides a method for transmitting a demodulation reference signal, including:

the transmitting device transmits a demodulation reference signal according to a demodulation reference signal pattern, wherein the time domain position of the demodulation reference signal in the demodulation reference signal pattern is one or more Orthogonal Frequency Division Multiplexing (OFDM) symbols which can be received by the receiving device and are not occupied by a common reference signal; the demodulation reference signal is used for coherent demodulation of downlink data transmission of the relay link.

Further, the air conditioner is provided with a fan,

when the subframe has a common Cyclic Prefix (CP) length, the time domain position of the demodulation reference signal is the 6 th OFDM symbol and the 7 th OFDM symbol; when the subframe has the extended CP length, the time domain position of the demodulation reference signal is the 5 th OFDM symbol and the 6 th OFDM symbol.

Further, the air conditioner is provided with a fan,

when a subframe has a common Cyclic Prefix (CP) length, the time domain position of the demodulation reference signal is the 6 th, 7 th, 13 th and 14 th OFDM symbols; when the subframe has the extended CP length, the time domain position of the demodulation reference signal is the 5 th, 6 th, 11 th and 12 th OFDM symbols.

Further, the air conditioner is provided with a fan,

when the subframe has a common CP length, the time domain position of the demodulation reference signal is the 5 th, 8 th, 9 th or 5 th, 8 th OFDM symbol of the subframe; when the subframe has the extended CP length, the time domain position of the demodulation reference signal is the 4 th, 7 th, 8 th or 4 th, 7 th or 7 th, 8 th or 7 th OFDM symbol of the subframe; the subframe is an MBSFN subframe.

Further, the air conditioner is provided with a fan,

when the subframe is a normal subframe and has a normal CP length, the time domain position of the demodulation reference signal is the 6 th OFDM symbol of the subframe; when the subframe has the extended CP length, the time domain position of the demodulation reference signal is the 5 th OFDM symbol of the subframe;

when the subframe is an MBSFN subframe and has a common CP length, the time domain position of the demodulation reference signal is the 5 th or 6 th or the 5 th, 6 th, 8 th or 9 th OFDM symbol of the subframe; when the subframe has the extended CP length, the time domain position of the demodulation reference signal is the 4 th, 5 th or 5 th, 7 th or 4 th, 5 th, 7 th, 8 th or 5 th, 7 th, 8 th OFDM symbol of the subframe.

Further, the air conditioner is provided with a fan,

the frequency domain positions of the demodulation reference signals are as follows:

in a resource block, the interval of demodulation reference signals of the same transmission layer or port in one OFDM symbol is 2 subcarriers, and the demodulation reference signals of the same transmission layer or port are transmitted on the resource block and 4 subcarriers in the OFDM symbol; or

In one resource block, the interval of the demodulation reference signal of the same transmission layer or port in one OFDM symbol is 4 subcarriers, and the demodulation reference signal of the same transmission layer or port is transmitted on the resource block and 3 subcarriers in the OFDM symbol.

Further, the air conditioner is provided with a fan,

the frequency domain positions of the demodulation reference signals are as follows:

in one resource block, the interval of the demodulation reference signal of the same transmission layer or port in one OFDM symbol is 5 or 9 subcarriers, and the demodulation reference signal of the same transmission layer or port is transmitted on the resource block and 2 subcarriers in the OFDM symbol.

Further, the air conditioner is provided with a fan,

the frequency domain positions of the demodulation reference signals are as follows:

in one resource block, the interval of the demodulation reference signal of the same transmission layer or port in one OFDM symbol is 5 subcarriers, and the demodulation reference signal of the same transmission layer or port is transmitted on the resource block and 2 subcarriers in the OFDM symbol.

Further, the air conditioner is provided with a fan,

when the number of layers or antenna ports for transmitting the demodulation reference signals is 2, performing orthogonal multiplexing on the demodulation reference signals of different transmission layers or antenna ports in a CDM or FDM mode;

when the number of layers or the number of antenna ports of the demodulation reference signal transmission is greater than 2, the demodulation reference signals of different transmission layers or antenna ports are subjected to orthogonal multiplexing in a mode of combining CDM and FDM.

Further, the air conditioner is provided with a fan,

when the demodulation reference signals are transmitted at a plurality of antenna ports, the demodulation reference signals of different antenna ports are subjected to orthogonal multiplexing in an FDM (frequency division multiplexing) mode or a mode of combining FDM and TDM (time division multiplexing).

Further, the air conditioner is provided with a fan,

the transmitting device generates the sequence of demodulation reference signals according to the following method:

the transmitting device generates a sequence of a common reference signal of each OFDM symbol according to the bandwidth of a downlink system, the cyclic prefix length of a subframe and a common reference signal pattern of a common subframe;

and the transmitting device takes the sequence corresponding to the resource block from the common reference signal sequence corresponding to the OFDM symbol l as the sequence of the relay link demodulation reference signal transmitted in the OFDM symbol l of the resource block according to the position of the resource block transmitted by the demodulation reference signal.

In order to solve the above technical problem, the present invention further provides a transmitting apparatus, including:

a storage module, configured to store the demodulation reference signal pattern, where a time domain position of the demodulation reference signal is one or more Orthogonal Frequency Division Multiplexing (OFDM) symbols that can be received by a receiving device and are not occupied by a common reference signal;

and the transmission module is used for sending the demodulation reference signal according to the demodulation reference signal pattern stored by the storage module.

Further, the air conditioner is provided with a fan,

when the subframe has a common Cyclic Prefix (CP) length, the time domain position of the demodulation reference signal is the 6 th OFDM symbol and the 7 th OFDM symbol; when the subframe has the extended CP length, the time domain position of the demodulation reference signal is the 5 th OFDM symbol and the 6 th OFDM symbol.

Further, the air conditioner is provided with a fan,

when a subframe has a common Cyclic Prefix (CP) length, the time domain position of the demodulation reference signal is the 6 th, 7 th, 13 th and 14 th OFDM symbols; when the subframe has the extended CP length, the time domain position of the demodulation reference signal is the 5 th, 6 th, 11 th and 12 th OFDM symbols;

further, the air conditioner is provided with a fan,

when the subframe has a common CP length, the time domain position of the demodulation reference signal is the 5 th, 8 th, 9 th or 5 th, 8 th OFDM symbol of the subframe; when the subframe has the extended CP length, the time domain position of the demodulation reference signal is the 4 th, 7 th, 8 th or 4 th, 7 th or 7 th, 8 th or 7 th OFDM symbol of the subframe; the subframe is an MBSFN subframe.

Further, the air conditioner is provided with a fan,

when the subframe is a normal subframe and has a normal CP length, the time domain position of the demodulation reference signal is the 6 th OFDM symbol of the subframe; when the subframe has the extended CP length, the time domain position of the demodulation reference signal is the 5 th OFDM symbol of the subframe;

when the subframe is an MBSFN subframe and has a common CP length, the time domain position of the demodulation reference signal is the 5 th or 6 th or the 5 th, 6 th, 8 th or 9 th OFDM symbol of the subframe; when the subframe has the extended CP length, the time domain position of the demodulation reference signal is the 4 th, 5 th or 5 th, 7 th or 4 th, 5 th, 7 th, 8 th or 5 th, 7 th, 8 th OFDM symbol of the subframe.

Further, the air conditioner is provided with a fan,

the frequency domain positions of the demodulation reference signals are as follows:

in a resource block, the interval of demodulation reference signals of the same transmission layer or port in one OFDM symbol is 2 subcarriers, and the demodulation reference signals of the same transmission layer or port are transmitted on the resource block and 4 subcarriers in the OFDM symbol; or

In one resource block, the interval of the demodulation reference signal of the same transmission layer or port in one OFDM symbol is 4 subcarriers, and the demodulation reference signal of the same transmission layer or port is transmitted on the resource block and 3 subcarriers in the OFDM symbol.

Further, the air conditioner is provided with a fan,

the frequency domain positions of the demodulation reference signals are as follows:

within one resource block, the interval of the demodulation reference signal of the same transmission layer or port within one OFDM symbol is 5 or 9 subcarriers, and the demodulation reference signal of the same transmission layer or port is transmitted on the resource block and 2 subcarriers within the OFDM symbol.

Further, the air conditioner is provided with a fan,

the frequency domain positions of the demodulation reference signals are as follows:

in one resource block, the interval of the demodulation reference signal of the same transmission layer or port in one OFDM symbol is 5 subcarriers, and the demodulation reference signal of the same transmission layer or port is transmitted on the resource block and 2 subcarriers in the OFDM symbol.

Further, the air conditioner is provided with a fan,

the transmitting device also comprises a common reference signal sequence generating module and a demodulation reference signal sequence generating module, wherein,

the common reference signal sequence generating module is used for generating a sequence of a common reference signal of each OFDM symbol according to the downlink system bandwidth, the sub-frame cyclic prefix length and a common reference signal pattern of a common sub-frame;

and the demodulation reference signal sequence generation module is used for taking a sequence corresponding to the resource block from a public reference signal sequence corresponding to the OFDM symbol l as a sequence of the relay link demodulation reference signal transmitted in the OFDM symbol l of the resource block according to the position of the resource block transmitted by the demodulation reference signal.

In order to solve the above technical problem, the present invention further provides a receiving apparatus, including:

a receiving module, configured to receive and analyze a demodulation reference signal, where a time domain position of the demodulation reference signal is one or more Orthogonal Frequency Division Multiplexing (OFDM) symbols that can be received by a receiving device and are not occupied by a common reference signal;

and the processing module is used for demodulating the data of the relay link according to the received downlink relay link demodulation reference signal.

The method for sending the demodulation reference signal and the transmitting and receiving device solve the transmission problem of the demodulation reference signal of the relay link, consider the overhead of the demodulation reference signal and ensure that the reliability of the downlink data transmission of the relay link and the overhead of the reference signal have a better compromise. Meanwhile, the demodulation reference signal transmission method avoids the conflict between the demodulation reference signal of the relay link and the CRS.

Drawings

FIG. 1 is a frame structure diagram of an LTE/LTE-A system;

fig. 2 is a resource structure diagram under a normal CP length;

fig. 3 is a schematic diagram of a downlink Relay subframe structure;

fig. 4 is a schematic diagram of CRS transmission in different subframe types;

FIG. 5 is a diagram illustrating a demodulation reference signal pattern according to embodiment 1 of the present invention;

fig. 6 is a schematic diagram of a demodulation reference signal pattern according to embodiment 1 of the present invention;

FIG. 7 is a diagram illustrating a demodulation reference signal pattern according to embodiment 2 of the present invention;

FIG. 8 is a diagram illustrating a demodulation reference signal pattern according to embodiment 2 of the present invention;

fig. 9 is a schematic diagram of a demodulation reference signal pattern according to embodiment 3 of the present invention;

fig. 10 is a schematic diagram of a demodulation reference signal pattern according to embodiment 3 of the present invention;

FIG. 11 is a diagram illustrating a demodulation reference signal pattern according to embodiment 4 of the present invention;

FIG. 12 is a diagram illustrating a demodulation reference signal pattern according to embodiment 4 of the present invention;

FIG. 13 is a diagram illustrating a demodulation reference signal pattern according to embodiment 4 of the present invention;

FIG. 14 is a diagram illustrating a demodulation reference signal pattern according to embodiment 4 of the present invention;

FIG. 15 is a diagram illustrating a demodulation reference signal pattern according to embodiment 5 of the present invention;

FIG. 16 is a diagram illustrating a demodulation reference signal pattern according to embodiment 5 of the present invention;

FIG. 17 is a diagram illustrating a demodulation reference signal pattern according to embodiment 5 of the present invention;

FIG. 18 is a diagram illustrating a demodulation reference signal pattern according to embodiment 5 of the present invention;

FIG. 19 is a diagram illustrating a demodulation reference signal pattern according to embodiment 5 of the present invention;

FIG. 20 is a diagram illustrating a demodulation reference signal pattern according to embodiment 6 of the present invention;

fig. 21 is a schematic diagram of a demodulation reference signal pattern according to embodiment 6 of the present invention;

FIG. 22 is a diagram illustrating a demodulation reference signal pattern according to embodiment 6 of the present invention;

fig. 23 is a schematic diagram of a demodulation reference signal pattern according to embodiment 6 of the present invention;

fig. 24 is a schematic diagram of a demodulation reference signal pattern according to embodiment 7 of the present invention;

FIG. 25 is a diagram illustrating a demodulation reference signal pattern according to embodiment 7 of the present invention;

fig. 26 is a schematic diagram of a demodulation reference signal pattern according to embodiment 7 of the present invention.

Detailed Description

The main idea of the demodulation reference signal sending method, the transmitting and receiving device of the present invention is that, in a demodulation reference signal pattern, a time domain position of the demodulation reference signal transmission is one or more Orthogonal Frequency Division Multiplexing (OFDM) symbols that can be received by a receiving device and are not occupied by a common reference signal.

The method for sending the demodulation reference signal comprises the following steps:

the transmitting device transmits a demodulation reference signal according to a pattern of the demodulation reference signal, wherein the time domain position of the demodulation reference signal in the pattern is one or more Orthogonal Frequency Division Multiplexing (OFDM) symbols which can be received by the receiving device and are not occupied by a common reference signal;

the invention provides three solutions for demodulation reference signal patterns:

firstly, a demodulation reference signal (DM-RS) pattern different from a LTE Common Reference Signal (CRS) pattern is designed for a relay link.

For example, when the subframe has a normal CP length, the demodulation reference signal is transmitted on the 6 th and 7 th OFDM symbols within the subframe; when the subframe has an extended CP length, the demodulation reference signal is transmitted on the 5 th and 6 th OFDM in the subframe. See subsequent examples 1-5 for details.

Secondly, reusing an LTE CRS pattern of the common subframe in part of resources as a demodulation reference signal pattern.

That is, if relay link data transmission occurs in an MBSFN subframe, a demodulation reference signal is designed to be transmitted in the subframe, and a transmitted demodulation reference signal pattern is the same as a CRS pattern transmitted in a corresponding resource position in a normal subframe. For example, if the demodulation reference signal is used for demodulation of relay link control data, and the subframe has a normal CP length, the demodulation reference signal is transmitted on the 5 th and 8 th OFDM symbols within the RB pair used for transmission of the relay link control data in the MBSFN subframe, and the demodulation reference signal has the same pattern as the CRS transmitted on the 5 th and 8 th OFDM symbols in the normal subframe. See example 6, infra, for details.

And thirdly, a demodulation reference signal is added on the basis of the CRS.

For example, assuming that the subframe for relay link data transmission is a normal subframe (non-MBSFN subframe), if the relay link downlink control information is transmitted only in the first slot of the relay subframe, there may be no CRS of ports 2 and 3 in the resource for transmitting the downlink control information in the first slot. In order to ensure the reliability of 4 ports of the relay link downlink control information during transmission, demodulation reference signals of two ports can be transmitted in the resources of the relay link downlink control information transmission, the demodulation reference signals of the two ports are respectively transmitted at the port 2 and the port 3 for transmitting the CRS, and the demodulation reference signals and the original CRS are used as the demodulation reference signals of the R-PDCCH together. See example 7, infra, for details.

The demodulation reference signal is used for coherent demodulation of downlink data transmission of a relay link and is only transmitted in a resource block pair of the downlink data transmission of the relay link; it may be transmitted in MBSFN subframes as well as in normal subframes (non-MBSFN subframes).

The downlink data may be relay link downlink control information, that is, information related to relay link scheduling, resource allocation, and the like; or may be relay link downlink service data (for example, the demodulation reference signal in embodiment 5 may be used to demodulate the service data).

When the demodulation reference signals are transmitted in a plurality of transmission layers or antenna ports, the demodulation reference signals of different layers or ports are orthogonally multiplexed in one or a combination of Frequency Division Multiplexing (FDM), Time Division Multiplexing (TDM) and Code Division Multiplexing (CDM).

When the number of layers or antenna ports for transmitting the demodulation reference signals is 2, performing orthogonal multiplexing on the demodulation reference signals of different transmission layers or antenna ports in a CDM or FDM mode;

when the number of layers or the number of antenna ports of the demodulation reference signal transmission is greater than 2, the demodulation reference signals of different transmission layers or antenna ports are subjected to orthogonal multiplexing in a mode of combining CDM and FDM.

When the demodulation reference signals are transmitted at a plurality of antenna ports, the demodulation reference signals of different antenna ports are subjected to orthogonal multiplexing in an FDM (frequency division multiplexing) mode or a mode of combining FDM and TDM (time division multiplexing).

By the method, the problem of transmission of the demodulation reference signal of the relay link is solved, the overhead of the demodulation reference signal is considered, a good compromise between the reliability of downlink data transmission of the relay link and the overhead of the reference signal is ensured, and the conflict between the demodulation reference signal of the relay link and the CRS is avoided.

The following detailed description of the demodulation reference signal pattern is made with reference to the accompanying drawings and embodiments:

example 1

In this example, it is assumed that the demodulation reference signal described in the present invention is used for demodulation of the relay link downlink control information, and that the relay link downlink control information is transmitted in a partial RB pair of the relay subframe and occupies a part of OFDM symbols within the RB pair used for transmission by the base station to the relay station. The control information is related information such as relay link scheduling and resource allocation.

In this example, the design principle of the demodulation reference signal pattern is that the time domain position of the demodulation reference signal transmission is an OFDM symbol that is not occupied by CRS transmission in the OFDM symbols that can be received by the relay station. Specifically, the demodulation reference signal is transmitted over 2 OFDM symbols. Within one resource block, the interval of the demodulation reference signals of the same transmission layer or port in one OFDM symbol is 4 subcarriers, and the demodulation reference signals of the same transmission layer or port are transmitted on 3 subcarriers within one OFDM symbol, and the specific frequency domain position is {1, 6, 11} th or {2, 7, 12} th subcarrier.

Under the assumption of this embodiment, a demodulation reference signal pattern supporting 1 port transmission under the normal CP length is as shown in fig. 5, specifically, the frequency domain position mapped in one RB by the demodulation reference signal is {1 st, 6 th, 11} th subcarrier; the mapped time domain position in the subframe is the {6, 7} th OFDM symbol.

While the pattern shown in fig. 5 may also support 2 port/layer transmission. The pattern for 2 port/layer transmission is the same as the pattern for 1 port transmission, except that the orthogonal multiplexing of demodulation reference signals of different ports/layers is performed by using a CDM orthogonal spreading mode. Wherein the RE of two demodulation reference signals adjacent in time domain is used as a spreading unit (as shown by the ellipse in fig. 5), and Walsh orthogonal code with length 2 is used as the spreading code, for example, the spreading codes of two ports/layers are taken as [1,1] and [1, -1], respectively.

Under the assumption of the present embodiment, an example of the demodulation reference signal pattern under the extended CP length is shown in fig. 6. The frequency domain position mapped by the demodulation reference signal in one RB is {1 st, 6 th, 11} th subcarrier; the mapped time domain position in the subframe is {5, 6} th OFDM symbol. The multiplexing mode of the demodulation reference signals of the two ports/layers is the same as the case of the normal CP length, and is not described herein again.

Example 2

Under the assumption of embodiment 1 and the design principle of the demodulation reference signal pattern, fig. 7 shows an example of the demodulation reference signal pattern supporting at most 4 port/layer transmission when the subframe has a normal CP length. Specifically, the multiplexing manner of the demodulation reference signals of the two ports/layers during the two-port/layer transmission is the same as that in embodiment 1, and is not described herein again; when the demodulation reference signals are transmitted at 4 ports/transmission layers, the ports/transmission layers are divided into two groups, the demodulation reference signals transmitted by the two ports/layers in each group are transmitted in the same multiplexing mode as that in two ports/transmission layers, that is, the demodulation reference signals of the two ports/layers are guaranteed to be orthogonal by adopting a CDM orthogonal frequency spreading mode, wherein REs of two demodulation reference signals adjacent to each other in a time domain are used as a spreading unit, the frequency spreading mode is the same as that in embodiment 1, and the demodulation reference signals between the two groups are kept orthogonal by adopting an FDM mode, for example, the demodulation reference signals of the two groups are transmitted on {1, 6, 11} and {2, 7, 12} subcarriers in one RB respectively.

Under the assumption of this embodiment, the demodulation reference signal pattern when the subframe has the extended CP length is shown in fig. 8, for example, the demodulation reference signal is transmitted on the {5, 6} th OFDM symbol in the subframe, and other frequency domain positions and multiplexing modes are the same as those in the case of the normal CP length, and are not described again here.

Also, an ellipse in fig. 7 and 8 represents one spreading unit at the time of CDM multiplexing.

Example 3

Under the assumption of embodiment 1, the design principle of the demodulation reference signal pattern in this example is that, within one RB, the demodulation reference signals of the same transmission layer or port are transmitted at 2 subcarriers in the frequency domain, and the demodulation reference signals of the same transmission layer or port are transmitted on 4 subcarriers within one OFDM symbol, the specific frequency domain position is {2, 5, 8, 11} th or {1, 4, 7, 10} or {3, 6, 9, 12} th subcarrier, and the transmission position of the demodulation reference signals in the time domain is the same as that in embodiment 1.

Under the assumption of this embodiment, a demodulation reference signal pattern supporting 1 port transmission under the normal CP length is as shown in fig. 9, specifically, the frequency domain position mapped in one RB by the demodulation reference signal is {2 th, 5 th, 8 th, 11} th subcarrier; the mapped time domain position in the subframe is the {6, 7} th OFDM symbol. While the pattern shown in fig. 9 may also support 2 port/layer transmission. And in the two-port/layer transmission, orthogonal multiplexing of demodulation reference signals of different ports/layers is carried out by adopting a CDM orthogonal spreading mode. Wherein RE of two demodulation reference signals adjacent in time domain is used as a spreading unit (as shown by an ellipse in fig. 9), Walsh orthogonal codes with length of 2 are used as spreading codes, for example, spreading codes of two ports are taken as [1,1] and [1, -1], respectively.

Under the assumption of the present embodiment, an example of the demodulation reference signal pattern under the extended CP length is shown in fig. 10. The frequency domain position mapped by the demodulation reference signal in one RB is {2 th, 5 th, 8 th, 11} th subcarrier; the mapped time domain position in the subframe is {5, 6} th OFDM symbol. The multiplexing mode of the demodulation reference signals of the two ports/layers is the same as the case of the normal CP length, and is not described herein again.

Example 4

In this example, it is assumed that the demodulation reference signal described in the present invention is used for demodulation of the downlink control information of the relay link, and that the downlink control information is transmitted in a part of RB pairs of the relay subframe and occupies all OFDM symbols within the RB pairs that are used for transmission from the base station to the relay station. The control information is related information such as relay link scheduling and resource allocation.

In this example, the design principle of the demodulation reference signal pattern is that the time domain position of the demodulation reference signal transmission is an OFDM symbol that is not occupied by CRS transmission in the OFDM symbols that can be received by the relay station. Specifically, the demodulation reference signal is transmitted over 4 OFDM symbols. Within one resource block, the interval of the demodulation reference signals of the same transmission layer or port in one OFDM symbol is 9 subcarriers, and the demodulation reference signals of the same transmission layer or port are transmitted on 2 subcarriers within one OFDM symbol, and the specific frequency domain position is {1, 11} th or {2, 12} th subcarrier.

Under the assumption of the present embodiment, the demodulation reference signal pattern supporting two-port/layer transmission under the normal CP length is as shown in fig. 11. Specifically, the demodulation reference signals of two ports/layers are orthogonally multiplexed in an FDM manner. The frequency domain positions of the reference signals of the two ports/layers mapped in one RB are respectively {1, 11} th subcarrier and {2, 12} th subcarrier; the time domain position mapped in the subframe is {6 th, 7 th, 13 th, 14} th OFDM symbol.

Under the assumption of the present embodiment, an example of the demodulation reference signal pattern under the extended CP length is shown in fig. 12. Specifically, the demodulation reference signals of two ports/layers are orthogonally multiplexed in an FDM manner. The frequency domain positions of the reference signals of the two ports/layers mapped in one RB are respectively {1, 11} th subcarrier and {2, 12} th subcarrier; the time domain positions mapped in the subframe are {5, 6, 11, 12} th OFDM symbols.

In this example, the interval of the demodulation reference signal of the same transmission layer or port in one OFDM symbol in one resource block may also be 5 subcarriers, and the demodulation reference signal of the same transmission layer or port is transmitted on 2 subcarriers in one OFDM symbol, where the specific frequency domain position is {3, 9} th or {4, 10} th subcarrier, and the demodulation reference signal patterns under the normal CP length and the extended CP length are shown in fig. 13 and 14, and are not described again.

In this example, if the transmission of the downlink control information occupies part of OFDM symbols in the relay subframe for the base station to transmit to the relay station, the demodulation reference signal described in the present invention may also be transmitted only in two OFDM symbols, for example, only on the {6, 7} th OFDM symbol under the normal CP length, and only on the {5, 6} th OFDM symbol under the extended CP length; the multiplexing mode and the frequency domain position of the demodulation reference signal are the same as those described above, and are not described again.

Example 5

In this example, the design principle of the demodulation reference signal pattern is that the time domain position of the demodulation reference signal transmission is an OFDM symbol that is not occupied by CRS transmission in the OFDM symbols that can be received by the relay station. Specifically, the demodulation reference signal is transmitted over 4 OFDM symbols. Within one resource block, the interval of the demodulation reference signals of the same transmission layer or port in one OFDM symbol is 9 subcarriers, and the demodulation reference signals of the same transmission layer port are transmitted on 2 subcarriers within one OFDM symbol, and the specific frequency domain position is {1, 11} th or {2, 12} th subcarrier.

Under the assumption of this embodiment, a demodulation reference signal pattern supporting 4-port/4-layer transmission under the normal CP length is shown in fig. 15, specifically, the frequency domain position mapped in one RB by the demodulation reference signal is {1, 11} th subcarrier; the time domain position mapped in the subframe is {6 th, 7 th, 13 th, 14} th OFDM symbol. The pattern of 2 port/2 layer transmission is the same as that of 1 port/1 layer transmission, and orthogonal multiplexing of demodulation reference signals of different ports/layers is performed by using a CDM orthogonal spreading mode. Wherein RE of two demodulation reference signals adjacent in time domain is used as a spreading unit (as shown by an ellipse in fig. 15), Walsh orthogonal codes with length of 2 are used as spreading codes, for example, spreading codes of two ports/layers are taken as [1,1] and [1, -1], respectively. When 4 ports/4 layers are transmitted, the ports/layers are divided into two groups, demodulation reference signals transmitted by two ports/layers in each group are in the same multiplexing mode as that in two-port transmission, that is, the demodulation reference signals of two ports/layers are guaranteed to be orthogonal by adopting a CDM orthogonal frequency spreading mode, wherein REs of two demodulation reference signals adjacent in a time domain are used as a spreading unit, and demodulation reference signals between two groups are orthogonally multiplexed by adopting an FDM mode, for example, the demodulation reference signals of two groups are respectively transmitted on {1, 11} and {2, 12} subcarriers in one RB.

Under the assumption of the present embodiment, an example of the demodulation reference signal pattern under the extended CP length is shown in fig. 16. The frequency domain position of the demodulation reference signal mapped in one RB is the same as that of the common CP length; the time domain positions mapped in the subframe are {5, 6, 11, 12} th OFDM symbols. The multiplexing mode of the multi-port/multi-layer demodulation reference signal is the same as the case of the normal CP length, and is not described herein again.

The demodulation reference signal described in this example may also support 8-layer transmission. The pattern of the demodulation reference signal transmitted by 8 layers is the same as that transmitted by 4 layers. Specifically, the transmission layers are divided into two groups, demodulation reference signals of the transmission layers in each group are orthogonally multiplexed by a CDM orthogonal spreading method, and the two groups are orthogonally multiplexed by an FDM method. The CDM orthogonal multiplexing scheme is that 4 demodulation reference signals RE on the same subcarrier within one RB are orthogonally spread as one spreading unit, and a pattern under the normal CP length is shown in fig. 17. Each layer uses Walsh codes of length 4 as orthogonal spreading codes. E.g., the spreading code is taken as

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

The demodulation reference signal under the extended CP length is processed by the same method, which is not described herein again.

Under the assumption of this example, the interval of the demodulation reference signals of the same port within one OFDM symbol may also be 5 subcarriers. Demodulation reference signal patterns supporting 4-layer transmission under the normal CP length and the extended CP length are shown in fig. 18 and 19, respectively. Demodulation reference signal patterns supporting 8-layer transmission can be similarly obtained, and are not described in detail here.

It should be noted that the CRS pattern of the LTE system is only schematically described in the diagrams of the above embodiments 1 to 5, and does not indicate the correspondence between the number of CRS ports and the number of demodulation reference signal ports/layers. And when the base station transmits data to the relay station using the MBSFN subframe, the CRS may not be present in OFDM symbols following the 3 rd OFDM symbol of the MBSFN subframe.

The demodulation reference signals in embodiments 1 to 5 are simultaneously suitable for transmission in normal subframes (non-MBSFN subframes) and MBSFN subframes. It should be noted that the demodulation reference signals in embodiments 1 to 4 are used for the coherent demodulation of the relay link downlink control information, while the demodulation reference signal in embodiment 5 may be used for the coherent demodulation of the relay link downlink control information, and may also be used for the coherent demodulation of the relay link downlink traffic information.

Example 6

In this example, it is assumed that the demodulation reference signal described in the present invention is used for demodulation of the relay link downlink control information, and that the relay link downlink control information is transmitted in a partial RB pair of the relay subframe and occupies a part of OFDM symbols within the RB pair used for transmission by the base station to the relay station. The control information is related information such as relay link scheduling and resource allocation.

In this example, the relay link downlink control information may be transmitted in a normal subframe (non-MBSFN subframe) or an MBSFN subframe. When transmitting in a common subframe, using CRS to carry out coherent demodulation; when the MBSFN subframe is transmitted, according to the protocol specification of LTE Rel-8, the CRS will not exist in the resource transmitted from the base station to the relay station, as shown in the right diagram of fig. 4.

The demodulation reference signal in this example is used for coherent demodulation of the downlink control information of the relay link during MBSFN subframe transmission. That is, if the base station transmits control information to the relay station using the MBSFN subframe, the demodulation reference signal is transmitted within the RB pair for the transmission of the control information in the MBSFN subframe. Specifically, the demodulation reference signals described in this example reuse the pattern of CRS of a normal subframe within a portion of OFDM symbols of the RB pair.

In this example, the number of ports of the demodulation reference signal is agreed to be the same as the number of CRS ports transmitted by the base station. For example, the CRS transmitted by the base station is 4 ports (CRS port number 0-3, the same below), the demodulation reference signal transmitted by the MBSFN subframe base station is also 4 ports, and the demodulation reference signal pattern under the normal CP length is as shown in fig. 20, that is, the demodulation reference signal is transmitted on the 5 th, 8 th, and 9 th OFDM symbols in the MBSFN subframe and reuses the CRS pattern of the normal subframe on the corresponding symbol. The demodulation reference signal pattern under the extended CP length is shown in fig. 21, i.e. the demodulation reference signal is transmitted on the 4 th, 7 th and 8 th OFDM symbols in the MBSFN subframe. If the relay station does not receive the 4 th OFDM symbol transmitted by the base station under the extended CP length, the demodulation reference signal is only transmitted on the 7 th and 8 th OFDM symbols. If the CRS transmitted by the base station is 1 or 2 ports, the demodulation reference signal transmitted by the base station in the MBSFN subframe is also 1 or 2 ports, that is, the demodulation reference signal is transmitted on the 5 th and 8 th OFDM symbols in the MBSFN subframe and reuses the CRS pattern of the normal subframe on the corresponding symbol, as shown in fig. 22. The demodulation reference signal is transmitted on the 4 th and 7 th OFDM symbols under the extended CP length, as shown in fig. 23; if the relay station does not receive the 4 th OFDM symbol transmitted by the base station, the demodulation reference signal is transmitted only on the 7 th OFDM symbol.

In this example, the number of ports for demodulation reference signal transmission may also be limited. For example, when the base station transmits CRSs of 1 or 2 ports, the transmitted demodulation reference signals are also 1 or 2 ports; when the CRS transmitted by the base station is 4 ports, the transmitted demodulation reference signal is limited to 2 ports. The demodulation reference signal pattern at the normal CP length is still as shown in fig. 22. The demodulation reference signal pattern at the extended CP length is still as shown in fig. 23. If the relay station does not receive the 4 th OFDM symbol transmitted by the base station under the extended CP length, the demodulation reference signal is only transmitted on the 7 th OFDM symbol.

Example 7

In this example, it is assumed that the demodulation reference signal described in the present invention is used for demodulation of the relay link downlink control information, and that the relay link downlink control information is transmitted in a partial RB pair of the relay subframe and occupies a part of OFDM symbols within the RB pair used for transmission by the base station to the relay station. The control information is related information such as relay link scheduling and resource allocation.

In this example, the relay link downlink control information may be transmitted in a normal subframe (non-MBSFN subframe) or an MBSFN subframe. When the CRS is transmitted in a common subframe, if the CRS transmitted by the base station is 1 or 2 ports, the relay station uses the CRS to demodulate the R-PDCCH; if the CRS transmitted by the base station is 4 ports, since there may be no CRS ports 2 or 3 in the downlink control domain of the relay link, demodulation reference signals of 2 ports are transmitted in the downlink control domain of the relay link, and the demodulation reference signals of two ports are transmitted in ports 2 and 3, respectively, through which the CRS is transmitted, so as to achieve the purpose that the transmission of the downlink control information of the relay link supports 4-antenna diversity. A schematic example of the demodulation reference signal transmission at the normal CP length is shown in fig. 24. And the position of a subcarrier of the demodulation reference signal in one RB is the same as the position of a subcarrier of CRS transmission of ports 2 and 3 in the 2 nd OFDM symbol in the subframe. Under the extended CP length, the demodulation reference signal is located in the 5 th OFDM symbol, and the rest is the same as the case of the normal CP length, and is not described herein again. The demodulation reference signals of the 2 ports described herein are transmitted only in the RB pair transmitted by the R-PDCCH, that is, the relay link downlink demodulation reference signals described in the present invention.

In this embodiment, the CRS is used together with demodulation reference signals for coherent demodulation in R-PDCCH four-antenna transmit diversity transmission.

If the relay link downlink control information is transmitted in the MBSFN subframe, the demodulation reference signal used for relay link downlink control information demodulation has the same pattern as the aforementioned CRS and demodulation reference signal transmitted in the normal subframe. That is, under the length of the normal CP, if the CRS is transmitted by using 1 or 2 ports, the demodulation reference signal is transmitted on the 5 th OFDM symbol; if the CRS is transmitted using 4 ports, the demodulation reference signal is transmitted on the 5 th and 6 th OFDM symbols, and the subcarrier positions are the same as those of the CRS and the demodulation reference signal transmitted in the 5 th and 6 th OFDM symbols in the normal subframe, as shown in fig. 25. Under the extended CP length, the OFDM symbols transmitted by the demodulation reference signal are 4 th and 5 th OFDM symbols, and other cases are the same as those of the normal CP length, which is not described herein again. If the 4 th OFDM symbol is not received by the relay station, the demodulation reference signal can be transmitted on the 5 th and 7 th OFDM symbols. The demodulation reference signal described herein is transmitted only in the RB pair of the relay link downlink control information transmission.

Under the assumption of this example, the demodulation reference signal pattern shown in fig. 26 may also be used for demodulation of the relay link control information transmitted in the MBSFN subframe, that is, on the basis of the pattern shown in fig. 25, the demodulation reference signals transmitted on the 8 th and 9 th OFDM symbols are added at the same time, and the demodulation reference signals also reuse the CRS pattern of the normal subframe. Under the extended CP length, the demodulation reference signal may be transmitted on the 4 th, 5 th, 7 th, and 8 th symbols, and if the relay station does not receive the 4 th OFDM symbol, the demodulation reference signal may be transmitted only on the 5 th, 7 th, and 8 th symbols, which is not described again.

It should be understood that the demodulation reference signal patterns in the embodiments are only for the purpose of describing and explaining the present invention, and are not intended to limit the present invention.

In order to implement the above method, the present invention also provides a transmitting apparatus, including:

a storage module, configured to store the demodulation reference signal pattern, where a time domain position of the demodulation reference signal is one or more Orthogonal Frequency Division Multiplexing (OFDM) symbols that can be received by a receiving device and are not occupied by a common reference signal;

specifically, the demodulation reference signal pattern is the same as that described in embodiments 1 to 7 above, and is not described herein again.

And the transmission module is used for sending the demodulation reference signal according to the demodulation reference signal pattern stored by the storage module.

In addition, the present invention also provides a receiving apparatus, comprising:

a receiving module, configured to receive and analyze a demodulation reference signal, where a time domain position of the demodulation reference signal is one or more Orthogonal Frequency Division Multiplexing (OFDM) symbols that can be received by a receiving device and are not occupied by a common reference signal;

specifically, the demodulation reference signal pattern is the same as that described in embodiments 1 to 7 above, and is not described herein again.

And the processing module is used for demodulating the data of the relay link according to the received downlink relay link demodulation reference signal.

The invention also provides a method for generating the demodulation reference signal sequence, which is particularly suitable for the situation that the demodulation reference signal reuses CRS patterns and comprises the following steps:

a, a base station generates a sequence of a common reference signal of each OFDM symbol according to a downlink system bandwidth, a subframe cyclic prefix length and a CRS pattern of a common subframe;

and B, taking a sequence corresponding to the resource block from a public reference signal sequence corresponding to the OFDM symbol l as a sequence of the relay link demodulation reference signal transmitted in the OFDM symbol l of the resource block according to the position of the resource block transmitted by the demodulation reference signal.

The common reference signal sequence described herein is generated in the same manner as in the LTE Rel-8 system.

For example, assuming that the demodulation reference signal is transmitted in the MBSFN subframe, and the demodulation reference signal reuses the CRS pattern of the normal subframe in some or all OFDM symbols in some RB pairs, a sequence corresponding to the corresponding RB and OFDM symbol (i.e., OFDM symbol transmitted with the demodulation reference signal) is taken as the sequence of the above demodulation reference signal transmitted in the MBSFN subframe in the CRS sequence.

In the LTE system, the generation formula of the CRS sequence is:

<math> <mrow> <msub> <mi>r</mi> <msub> <mrow> <mi>l</mi> <mo>,</mo> <mi>n</mi> </mrow> <mi>s</mi> </msub> </msub> <mrow> <mo>(</mo> <mi>m</mi> <mo>)</mo> </mrow> <mo>=</mo> <mfrac> <mn>1</mn> <msqrt> <mn>2</mn> </msqrt> </mfrac> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <mn>2</mn> <mo>&CenterDot;</mo> <mi>c</mi> <mrow> <mo>(</mo> <mn>2</mn> <mi>m</mi> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mo>+</mo> <mi>j</mi> <mfrac> <mn>1</mn> <msqrt> <mn>2</mn> </msqrt> </mfrac> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <mn>2</mn> <mo>&CenterDot;</mo> <mi>c</mi> <mrow> <mo>(</mo> <mn>2</mn> <mi>m</mi> <mo>+</mo> <mn>1</mn> <mo>)</mo> </mrow> <mo>)</mo> </mrow> <mo>,</mo> <mi>m</mi> <mo>=</mo> <mn>0,1</mn> <mo>,</mo> <mo>.</mo> <mo>.</mo> <mo>.</mo> <mo>,</mo> <msubsup> <mrow> <mn>2</mn> <mi>N</mi> </mrow> <mi>RB</mi> <mrow> <mi>max</mi> <mo>,</mo> <mi>DL</mi> </mrow> </msubsup> <mo>-</mo> <mn>1</mn> </mrow> </math>

where l is the OFDM symbol number in the slot, n_sIs the slot number within the radio frame, c (-) is a pseudo-random sequence defined in the LTE protocol,is the maximum number of available RBs in the downlink system bandwidth. The sequence generation formula is explained in detail in the LTE Rel-8 protocol, and is not described herein again. As can be seen from the above formula, in the LTE system, CRS transmission is adoptedWithin an OFDM symbol, CRS of one port occupies 2 REs in one RB. For example, for the downlink number iFor an RB of (1), the CRS sequence transmitted by an antenna port on OFDM symbol l of the RB is { r_l,ns(2i),r_l,ns(2i+1)}。

If a demodulation reference signal is transmitted in a partial RB on an OFDM symbol l of an MBSFN subframe and a CRS pattern of the OFDM symbol (l) of a common subframe is reused in the partial RB, the sequence of the demodulation reference signal of a certain port in the corresponding OFDM symbol l in the RB transmitted by the demodulation reference signal is { r_l,ns(2i),r_l,ns(2i +1) }, in which iFor the numbering of this RB within the downlink system bandwidth,as defined above.

It should be understood that the demodulation reference signal sequence described in this example is only for the purpose of describing and explaining the present invention, and is not intended to limit the present invention.

In order to realize the above demodulation reference signal sequence generation method, the transmitting apparatus of the present invention further comprises a common reference signal sequence generation module and a demodulation reference signal sequence generation module, wherein,

the common reference signal sequence generating module is used for generating a sequence of a common reference signal of each OFDM symbol according to the downlink system bandwidth, the sub-frame cyclic prefix length and the CRS pattern of the common sub-frame;

and the demodulation reference signal sequence generation module is used for taking a sequence corresponding to the resource block from a public reference signal sequence corresponding to the OFDM symbol l as a sequence of the relay link demodulation reference signal transmitted in the OFDM symbol l of the resource block according to the position of the resource block transmitted by the demodulation reference signal.

It will be apparent to those skilled in the art that the modules or steps of the present invention described above may be implemented by a general purpose computing device, they may be centralized on a single computing device or distributed across a network of multiple computing devices, and they may alternatively be implemented by program code executable by a computing device, such that they may be stored in a storage device and executed by a computing device, or fabricated separately as individual integrated circuit modules, or fabricated as a single integrated circuit module from multiple modules or steps. Thus, the present invention is not limited to any specific combination of hardware and software.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

In summary, by the above method, the problem of transmission of the demodulation reference signal of the relay link is solved, and meanwhile, the overhead of the demodulation reference signal is considered, so that a better compromise is ensured between the reliability of downlink data transmission of the relay link and the overhead of the reference signal, and the collision between the demodulation reference signal of the relay link and the common reference signal CRS is avoided.

Claims (16)

1. A method for transmitting a demodulation reference signal, the method comprising:

the transmitting device transmits a demodulation reference signal according to a demodulation reference signal pattern, wherein the time domain position of the demodulation reference signal in the demodulation reference signal pattern is one or more Orthogonal Frequency Division Multiplexing (OFDM) symbols which can be received by the receiving device and are not occupied by a common reference signal; the demodulation reference signal is used for coherent demodulation of downlink data transmission of the relay link;

the frequency domain positions of the demodulation reference signals are as follows:

in a resource block, the interval of demodulation reference signals of the same transmission layer or port in one OFDM symbol is 5 subcarriers, and the demodulation reference signals of the same transmission layer or port are transmitted on the resource block and 2 subcarriers in the OFDM symbol;

when the subframe has a common CP length, the time domain position of the demodulation reference signal is the 5 th, 8 th, 9 th or 5 th, 8 th OFDM symbol of the subframe; when the subframe has the extended CP length, the time domain position of the demodulation reference signal is the 4 th, 7 th, 8 th or 4 th, 7 th or 7 th, 8 th or 7 th OFDM symbol of the subframe; the subframe is an MBSFN subframe;

or,

under the condition that the subframe is a common subframe and has a common CP length, the time domain position of the demodulation reference signal is the 6 th OFDM symbol of the subframe; when the subframe has the extended CP length, the time domain position of the demodulation reference signal is the 5 th OFDM symbol of the subframe; when the subframe is an MBSFN subframe and has a common CP length, the time domain position of the demodulation reference signal is the 5 th or 6 th or the 5 th, 6 th, 8 th or 9 th OFDM symbol of the subframe; when the subframe has the extended CP length, the time domain position of the demodulation reference signal is the 4 th, 5 th or 5 th, 7 th or 4 th, 5 th, 7 th, 8 th or 5 th, 7 th, 8 th OFDM symbol of the subframe.

2. The method of claim 1, wherein:

when the subframe has a common Cyclic Prefix (CP) length, the time domain position of the demodulation reference signal is the 6 th OFDM symbol and the 7 th OFDM symbol; when the subframe has the extended CP length, the time domain position of the demodulation reference signal is the 5 th OFDM symbol and the 6 th OFDM symbol.

3. The method of claim 1, wherein:

when a subframe has a common Cyclic Prefix (CP) length, the time domain position of the demodulation reference signal is the 6 th, 7 th, 13 th and 14 th OFDM symbols; when the subframe has the extended CP length, the time domain position of the demodulation reference signal is the 5 th, 6 th, 11 th and 12 th OFDM symbols.

4. The method of claim 1 or 2,

the frequency domain positions of the demodulation reference signals are as follows:

in a resource block, the interval of demodulation reference signals of the same transmission layer or port in one OFDM symbol is 2 subcarriers, and the demodulation reference signals of the same transmission layer or port are transmitted on the resource block and 4 subcarriers in the OFDM symbol; or

In one resource block, the interval of the demodulation reference signal of the same transmission layer or port in one OFDM symbol is 4 subcarriers, and the demodulation reference signal of the same transmission layer or port is transmitted on the resource block and 3 subcarriers in the OFDM symbol.

5. The method according to any one of claims 1 to 3,

the frequency domain positions of the demodulation reference signals are as follows:

in one resource block, the interval of the demodulation reference signal of the same transmission layer or port in one OFDM symbol is 5 or 9 subcarriers, and the demodulation reference signal of the same transmission layer or port is transmitted on the resource block and 2 subcarriers in the OFDM symbol.

6. The method of claim 1, wherein:

when the number of layers or antenna ports for transmitting the demodulation reference signals is 2, performing orthogonal multiplexing on the demodulation reference signals of different transmission layers or antenna ports in a CDM or FDM mode;

when the number of layers or the number of antenna ports of the demodulation reference signal transmission is greater than 2, the demodulation reference signals of different transmission layers or antenna ports are subjected to orthogonal multiplexing in a mode of combining CDM and FDM.

7. The method of claim 1, wherein:

when the demodulation reference signals are transmitted at a plurality of antenna ports, the demodulation reference signals of different antenna ports are subjected to orthogonal multiplexing in an FDM (frequency division multiplexing) mode or a mode of combining FDM and TDM (time division multiplexing).

8. The method of claim 1, wherein: the transmitting device generates the sequence of demodulation reference signals according to the following method:

the transmitting device generates a sequence of a common reference signal of each OFDM symbol according to the bandwidth of a downlink system, the cyclic prefix length of a subframe and a common reference signal pattern of a common subframe;

and the transmitting device takes the sequence corresponding to the resource block from the common reference signal sequence corresponding to the OFDM symbol l as the sequence of the relay link demodulation reference signal transmitted in the OFDM symbol l of the resource block according to the position of the resource block transmitted by the demodulation reference signal.

9. A transmitting apparatus, the apparatus comprising:

a storage module, configured to store a demodulation reference signal pattern, where a time domain position of the demodulation reference signal is one or more Orthogonal Frequency Division Multiplexing (OFDM) symbols that can be received by a receiving device and are not occupied by a common reference signal;

the transmission module is used for sending demodulation reference signals according to the demodulation reference signal patterns stored by the storage module;

the frequency domain positions of the demodulation reference signals are as follows:

in a resource block, the interval of demodulation reference signals of the same transmission layer or port in one OFDM symbol is 5 subcarriers, and the demodulation reference signals of the same transmission layer or port are transmitted on the resource block and 2 subcarriers in the OFDM symbol;

when the subframe has a common CP length, the time domain position of the demodulation reference signal is the 5 th, 8 th, 9 th or 5 th, 8 th OFDM symbol of the subframe; when the subframe has the extended CP length, the time domain position of the demodulation reference signal is the 4 th, 7 th, 8 th or 4 th, 7 th or 7 th, 8 th or 7 th OFDM symbol of the subframe; the subframe is an MBSFN subframe;

or,

under the condition that the subframe is a common subframe and has a common CP length, the time domain position of the demodulation reference signal is the 6 th OFDM symbol of the subframe; when the subframe has the extended CP length, the time domain position of the demodulation reference signal is the 5 th OFDM symbol of the subframe; when the subframe is an MBSFN subframe and has a common CP length, the time domain position of the demodulation reference signal is the 5 th or 6 th or the 5 th, 6 th, 8 th or 9 th OFDM symbol of the subframe; when the subframe has the extended CP length, the time domain position of the demodulation reference signal is the 4 th, 5 th or 5 th, 7 th or 4 th, 5 th, 7 th, 8 th or 5 th, 7 th, 8 th OFDM symbol of the subframe.

10. The apparatus of claim 9, wherein:

when the subframe has a common Cyclic Prefix (CP) length, the time domain position of the demodulation reference signal is the 6 th OFDM symbol and the 7 th OFDM symbol; when the subframe has the extended CP length, the time domain position of the demodulation reference signal is the 5 th OFDM symbol and the 6 th OFDM symbol.

11. The apparatus of claim 9, wherein:

when a subframe has a common Cyclic Prefix (CP) length, the time domain position of the demodulation reference signal is the 6 th, 7 th, 13 th and 14 th OFDM symbols; when the subframe has the extended CP length, the time domain position of the demodulation reference signal is the 5 th, 6 th, 11 th and 12 th OFDM symbols.

12. The apparatus of claim 9 or 10,

the frequency domain positions of the demodulation reference signals are as follows:

in a resource block, the interval of demodulation reference signals of the same transmission layer or port in one OFDM symbol is 2 subcarriers, and the demodulation reference signals of the same transmission layer or port are transmitted on the resource block and 4 subcarriers in the OFDM symbol; or

In one resource block, the interval of the demodulation reference signal of the same transmission layer or port in one OFDM symbol is 4 subcarriers, and the demodulation reference signal of the same transmission layer or port is transmitted on the resource block and 3 subcarriers in the OFDM symbol.

13. The apparatus according to any one of claims 9 to 11,

the frequency domain positions of the demodulation reference signals are as follows:

within one resource block, the interval of the demodulation reference signal of the same transmission layer or port within one OFDM symbol is 5 or 9 subcarriers, and the demodulation reference signal of the same transmission layer or port is transmitted on the resource block and 2 subcarriers within the OFDM symbol.

14. The apparatus of claim 9, wherein:

the transmitting device also comprises a common reference signal sequence generating module and a demodulation reference signal sequence generating module, wherein,

the common reference signal sequence generating module is used for generating a sequence of a common reference signal of each OFDM symbol according to the downlink system bandwidth, the sub-frame cyclic prefix length and a common reference signal pattern of a common sub-frame;

and the demodulation reference signal sequence generation module is used for taking a sequence corresponding to the resource block from a public reference signal sequence corresponding to the OFDM symbol l as a sequence of the relay link demodulation reference signal transmitted in the OFDM symbol l of the resource block according to the position of the resource block transmitted by the demodulation reference signal.

15. A receiving apparatus, characterized in that the apparatus comprises:

a receiving module, configured to receive and analyze a demodulation reference signal, where a time domain position of the demodulation reference signal is one or more Orthogonal Frequency Division Multiplexing (OFDM) symbols that can be received by a receiving device and are not occupied by a common reference signal;

the processing module is used for demodulating the data of the relay link according to the received downlink relay link demodulation reference signal;

the frequency domain positions of the demodulation reference signals are as follows:

in a resource block, the interval of demodulation reference signals of the same transmission layer or port in one OFDM symbol is 5 subcarriers, and the demodulation reference signals of the same transmission layer or port are transmitted on the resource block and 2 subcarriers in the OFDM symbol;

when the subframe has a common CP length, the time domain position of the demodulation reference signal is the 5 th, 8 th, 9 th or 5 th, 8 th OFDM symbol of the subframe; when the subframe has the extended CP length, the time domain position of the demodulation reference signal is the 4 th, 7 th, 8 th or 4 th, 7 th or 7 th, 8 th or 7 th OFDM symbol of the subframe; the subframe is an MBSFN subframe;

or,

under the condition that the subframe is a common subframe and has a common CP length, the time domain position of the demodulation reference signal is the 6 th OFDM symbol of the subframe; when the subframe has the extended CP length, the time domain position of the demodulation reference signal is the 5 th OFDM symbol of the subframe; when the subframe is an MBSFN subframe and has a common CP length, the time domain position of the demodulation reference signal is the 5 th or 6 th or the 5 th, 6 th, 8 th or 9 th OFDM symbol of the subframe; when the subframe has the extended CP length, the time domain position of the demodulation reference signal is the 4 th, 5 th or 5 th, 7 th or 4 th, 5 th, 7 th, 8 th or 5 th, 7 th, 8 th OFDM symbol of the subframe.

16. A method for generating a demodulation reference signal sequence, the method comprising:

the transmitting device generates a sequence of a common reference signal of each OFDM symbol according to the bandwidth of a downlink system, the cyclic prefix length of a subframe and a CRS pattern of a common subframe;

the transmitting device takes a sequence corresponding to the resource block from a public reference signal sequence corresponding to the OFDM symbol l as a sequence of a relay link demodulation reference signal transmitted in the OFDM symbol l of the resource block according to the position of the resource block transmitted by the demodulation reference signal;

when the subframe has a common CP length, the time domain position of the demodulation reference signal is the 5 th, 8 th, 9 th or 5 th, 8 th OFDM symbol of the subframe; when the subframe has the extended CP length, the time domain position of the demodulation reference signal is the 4 th, 7 th, 8 th or 4 th, 7 th or 7 th, 8 th or 7 th OFDM symbol of the subframe; the subframe is an MBSFN subframe;

or,

under the condition that the subframe is a common subframe and has a common CP length, the time domain position of the demodulation reference signal is the 6 th OFDM symbol of the subframe; when the subframe has the extended CP length, the time domain position of the demodulation reference signal is the 5 th OFDM symbol of the subframe; when the subframe is an MBSFN subframe and has a common CP length, the time domain position of the demodulation reference signal is the 5 th or 6 th or the 5 th, 6 th, 8 th or 9 th OFDM symbol of the subframe; when the subframe has the extended CP length, the time domain position of the demodulation reference signal is the 4 th, 5 th or 5 th, 7 th or 4 th, 5 th, 7 th, 8 th or 5 th, 7 th, 8 th OFDM symbol of the subframe.