# US 8,787,245 B2 · Backhaul downlink signal decoding method of relay station and relay station using same

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- Number: US 8,787,245 B2
- Document ID: US8787245B2
- Status: Granted
- Kind: B2
- Application number: 13/503,740
- Filed: 2010-10-22
- Published: 2012-08-16
- Granted: 2014-07-22
- Earliest claimed: 2009-10-25
- Assignees: LG Electronics Inc.
- Applicants: Han Byul Seo; Dae Won Lee; Byoung Hoon Kim; Hak Seong Kim; Ki Jun Kim
- Inventors: Han Byul Seo; Dae Won Lee; Byoung Hoon Kim; Hak Seong Kim; Ki Jun Kim
- Web page: https://patentgrep.com/patent/US8787245B2

## CPC

- H04L 27/2613: {Structure of the reference signals}
- H04B 7/155: Ground-based stations (H04B7/204 takes precedence)
- H04B 7/15542: {Selecting at relay station its transmit and receive resources (selection of wireless resources by user or terminal H04W72/02; arrangements affording multiple use of the transmission path by two-dimensional division of the resources H04L5/0003, or by allocating sub-channels H04L5/003)}
- H04B 7/2606: {Arrangements for base station coverage control, e.g. by using relays in tunnels}
- H04L 5/0005: {Time-frequency}
- H04L 5/0023: {Time-frequency-space}
- H04L 5/0051: {of dedicated pilots, i.e. pilots destined for a single user or terminal}
- H04L 5/0053: {Allocation of signalling, i.e. of overhead other than pilot signals}
- H04L 27/2647: {Arrangements specific to the receiver only (equalisation H04L27/01)}
- H04W 16/26: Cell enhancers {or enhancement}, e.g. for tunnels, building shadow
- H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal
- H04W 84/042: {Public Land Mobile systems, e.g. cellular systems}
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04B: TRANSMISSION
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

A method of decoding a backhaul downlink signal of a relay station is provided. The method includes: receiving by the relay station a transmission rank value for a backhaul downlink from a base station through a high-layer signal; receiving control information from the base station through a control region; and decoding the control information, wherein the transmission rank value for the backhaul downlink is a transmission rank value assumed when the relay station decodes the control information, and wherein the control information is mapped to a resource element which does not overlap with a dedicated reference signal resource element mapped to the control region by assuming the transmission rank value for the backhaul downlink.

## Claims

### Claim 1

A method of decoding a backhaul downlink signal of a relay node (RN), the method comprising:
receiving a higher layer signal indicating a maximum transmission rank from a base station (BS);
receiving control information through a relay control channel from the BS; and
decoding the control information,
wherein the control information is mapped to resource elements which do not overlap with user equipment-specific reference signal (URS) resource elements in a control region which is used for the relay control channel transmission of the BS, and
wherein the URS resource elements are reserved resource elements for URSs according to the maximum transmission rank.

### Claim 2 (depends on 1)

The method of claim 1, wherein the control region is located in a first slot of a subframe, the subframe comprises two slots and each slot of the two slots comprises a plurality of resource elements.

### Claim 3 (depends on 2)

The method of claim 2, wherein each of the plurality of resource elements comprises an orthogonal frequency division multiplexing(OFDM) symbol in time domain and a subcarrier in frequency domain.

### Claim 4 (depends on 1)

The method of claim 1, wherein the maximum transmission rank is equal to a maximum rank that can be transmitted between the base station and the RN.

### Claim 5 (depends on 1)

The method of claim 1, further comprising:
receiving data through a data channel; and
decoding the data, wherein UE-specific reference signals used to decode the data include a UE-specific reference signal used to decode the control information.

### Claim 6 (depends on 5)

The method of claim 5, wherein the data channel is received in a same subframe in which the relay control channel is received.

### Claim 7 (depends on 1)

The method of claim 1, wherein the higher layer signal is a radio resource control (RRC) message.

### Claim 8

A relay Node (RN) comprising:
a radio frequency (RF) unit for transmitting and receiving a radio signal; and
a processor coupled to the RF unit,
wherein the processor is configured for:
receiving a higher layer signal indicating a maximum transmission rank from a base station (BS);
receiving control information through a relay control channel from the BS; and
decoding the control information,
wherein the control information is mapped to resource elements which do not overlap with user equipment-specific reference signal (URS) resource elements in a control region which is used for the relay control channel transmission of the BS, and
wherein the URS resource elements are reserved resource elements for URSs according to the maximum transmission rank.

### Claim 9 (depends on 8)

The RN of claim 8, wherein the control region is located in a first slot of a subframe, the subframe comprises two slots and each slot of the two slots comprises a plurality of resource elements.

### Claim 10 (depends on 8)

The RN of claim 8, wherein each of the plurality of resource elements comprises an orthogonal frequency division multiplexing(OFDM) symbol in time domain and a subcarrier in frequency domain.

### Claim 11 (depends on 8)

The RN of claim 8, wherein the control information is mapped to resource elements which do not overlap with UE-specific reference signal resource elements mapped to the control region.

### Claim 12 (depends on 8)

The RN of claim 8, wherein the maximum transmission rank is equal to a maximum rank that can be transmitted between the base station and the RN.

### Claim 13 (depends on 8)

The RN of claim 8, the processor further configured for:
receiving data through a data region; and
decoding the data, wherein UE-specific reference signals used to decode the data include a UE-specific reference signal used to decode the control information.

### Claim 14 (depends on 8)

The RN of claim 8, wherein the data channel is received in a same subframe in which the relay control channel is received.

### Claim 15 (depends on 8)

The RN of claim 8, wherein the higher layer signal is a radio resource control (RRC) message.