Apparatus and method for transparent relay in multihop relay broadband wireless access (BWA) communication system

• US 20070153734A1
• Filed: 01/03/2007
• Published: 07/05/2007
• Est. Priority Date: 01/03/2006
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Park, Jeong-Ho, Cho, Jae-Weon, Lee, Mi-Hyun, Hong, Song-Nam, Choi, Joon-Young, Joo, Pan-Yuh
• Application Number:
  US11/649,153
• Publication Number:
  US 20070153734A1
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04B 7/2606 Arrangements for base station coverage control, e.g. by using relays in tunnels
• CPC Class Codes: H04L 27/2656 Frame synchronisation, e.g. packet synchronisation, time division duplex [TDD] switching point detection or subframe synchronisation
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0032 Distributed allocation, i.e. involving a plurality of allocating devices, each making partial allocation
• CPC Class Codes: H04L 5/005 of common pilots, i.e. pilots destined for multiple users or terminals

Abstract

An apparatus and method of transparently relaying a signal in a direct link and a relay link using the same frequency band in a multihop relay Broadband Wireless Access (BWA) communication system. The method includes designating a start point of an asynchronous frame of the relay link by taking into account of a broadcast channel transmission interval of the direct link frame; and making a frame interval of the relay link null, where a transmission (Tx) mode of the direct link overlaps with another Tx mode. Accordingly, serving cell service coverage expansion and backward compatibility are achieved and a frame is constructed by selecting an optimum frame interval according to system information of the serving cell service. Therefore, efficient wireless access service can be provided.

Claims

1. A subframe construction method of supporting a relay service using one frequency band in a wireless communication system, the method comprising:

constructing a direct link subframe to communicate in a direct link between a Base Station (BS) and a Relay Station (RS) or a Mobile Station (MS) during a first interval of the subframe; and

constructing a direct link subframe to communicate in a direct link between the BS and an MS, and a relay link subframe to communicate in a relay link between the RS and an MS during a second interval of the subframe.

2. The subframe construction method of claim 1, wherein the direct link subframe and the relay link subframe in the second interval are constructed through a spatial multiplexing in the same frequency band.

3. The subframe construction method of claim 1, wherein the relay link subframe in the second interval designates a start point in asynchrony to the direct link subframe.

4. The subframe construction method of claim 3, wherein, when the direct link frame and the relay link frame in a certain interval have different transmission (Tx) modes, the relay link frame of the certain interval is null.

5. A method of supporting a relay service using one frequency band at a Base Station (BS) in a wireless communication system, the method comprising:

setting a direct link frame interval for providing service to a Relay Station (RS) or a Mobile Station (MS) in a direct link;

designating a start point of a relay link frame for providing service between the RS and the MS according to a Broadcast Channel (BCH) transmission interval in the direct link frame;

sending start point information of the relay link frame to the RS; and

communicating with one of the RS and an MS according to the direct link frame construction scheme.

6. The method of claim 5, wherein the start point of the relay link frame is between an end point of the BCH of the direct link frame and a start point of an uplink (UL) transmission interval of the direct link frame.

7. The method of claim 5, wherein the BCH comprises a preamble signal and control information.

8. The method of claim 5, wherein the relay link frame is constructed through a spatial multiplexing in the same frequency band as the direct link frame.

9. The method of claim 5, wherein the direct link frame comprises a first interval for communicating with one of the RS and an MS in the direct link, and a second interval for communicating with the MS in the direct link.

10. A frame construction method of supporting a relay service using one frequency band in a wireless communication system, the method comprising:

constructing a direct link subframe for a Base Station (BS) to send a signal to a Relay Station (RS) or a Mobile Station (MS) in a direct link during a first interval of the frame;

constructing a relay link subframe for the RS to send a signal to the MS in a relay link during a second interval of the frame;

constructing a direct link subframe for the BS to send a signal to the MS in a direct link during a third interval of the frame;

constructing a direct link subframe for one of the RS and the MS to send a signal to the BS in a direct link during a fourth interval of the frame; and

constructing a relay link subframe for the MS to send a signal to the RS in a relay link during a fifth interval of the frame.

11. The frame construction method of claim 10, wherein the direct link subframe is null during the second interval and the fourth interval.

12. The frame construction method of claim 10, wherein the relay link subframe is null during the first interval, the third interval, and the fifth interval.

13. A method of supporting a relay service using one frequency band at a Base Station (BS) of a wireless communication system, the method comprising:

setting a direct link frame interval for communicating with a Relay Station (RS) or a Mobile Station (MS) in a direct link;

setting a relay link frame interval for communicating between the RS and the MS in relay link;

constructing a frame by time-dividing the frame interval to a certain number of intervals and allocating the intervals to a direct link frame or a relay link frame; and

sending the frame construction information to the RS and the MS.

14. The method of claim 13, wherein the direct link frame interval is a length of the frame.

15. The method of claim 13, wherein the frame time-dividing step comprises:

determining a first ratio of an uplink (UL) interval to a downlink (DL) interval and ratio of a relay link service interval to a direct link service interval within the frame interval;

determining a length of each interval for dividing the frame to the certain number of intervals using the frame interval, the first ratio, and the second ratio; and

time-dividing the frame interval based on the length of each interval.

16. The method of claim 15, wherein the length of each interval is calculated base on the equation:

$\begin{array}{c}{x}_1=\frac{a\times <br><br>c}{\left(b+1\right)<br><br>\left(c+1\right)}\\ x_2=\frac{a\times <br><br>b}{\left(b+1\right)<br><br>\left(c+1\right)}\\ x_3=\frac{\left(b-1\right)\times <br><br>a\times <br><br>c}{\left(b+1\right)<br><br>\left(c+1\right)}\\ x_4=\frac{a\times <br><br>c}{\left(b+1\right)<br><br>\left(c+1\right)}\\ x_5=\frac{a}{\left(b+1\right)<br><br>\left(c+1\right)}\end{array}$

where x₁, X₂, X₃, x₄, and x₅ denote a length of the respective intervals, a denotes a direct link frame interval, b denotes a ratio of the UL interval to the DL interval, and c denotes a ratio of the direct link frame interval to the relay link frame interval.

17. The method of claim 13, wherein the frame constructing step comprises:

making the relay link frame null in an interval allocated to the direct link frame; and

making the direct link frame null in an interval allocated to the relay link frame.

18. The method of claim 13, wherein the frame constructing step comprises:

when dividing the frame to five intervals, constructing a direct link subframe for the BS to send a signal to one of the RS and the MS in a direct link during a first interval;

constructing a relay link subframe for the RS to send a signal to the MS in a relay link during a second interval;

constructing a direct link subframe for the BS to send a signal to the MS in a direct link during a third interval;

constructing a direct link subframe for one of the RS and the MS to send a signal to the BS in a direct link during a fourth interval; and

constructing a relay link subframe for the MS to send a signal to the RS in a relay link during a fifth interval.

19. An apparatus for supporting a relay service using one frequency band at a Base Station (BS) in a wireless communication system, comprising:

a time slot divider for calculating a length of a time slot according to a frame length, a ratio of an uplink (UL) interval to a downlink (DL) interval, a ratio of a direct link service interval to a relay link service interval, and a number of time slots;

a timing controller for providing a timing signal to transmit and receive a signal according to the calculated length of the time slot;

a transmitter for sending a signal of a corresponding frequency band according to the timing signal; and

a receiver for receiving a signal of a corresponding frequency band according to the timing signal.

20. The apparatus of claim 19, wherein the time slot divider is comprising:

means for checking a ratio of a direct link service interval to a relay link service interval within the direct link frame and the number of time slots to be divided, and

means for calculating the length of the time slot based on the frame length, the ratio of the UL interval to the DL interval, the ratio of the direct link service interval to the relay link service interval, and the number of the time slots.

21. The apparatus of claim 20, wherein the time slot divider calculates the length of the time slots of each interval based on the equation:

$\begin{array}{c}{x}_1=\frac{a\times <br><br>c}{\left(b+1\right)<br><br>\left(c+1\right)}\\ x_2=\frac{a\times <br><br>b}{\left(b+1\right)<br><br>\left(c+1\right)}\\ x_3=\frac{\left(b-1\right)\times <br><br>a\times <br><br>c}{\left(b+1\right)<br><br>\left(c+1\right)}\\ x_4=\frac{a\times <br><br>c}{\left(b+1\right)<br><br>\left(c+1\right)}\\ x_5=\frac{a}{\left(b+1\right)<br><br>\left(c+1\right)}\end{array}$

where x₁, X₂, x₃, x₄, and x₅ denote a length of the respective intervals, a denotes a direct link frame interval, b denotes the ratio of the UL interval to the DL interval, and c denotes the ratio of the direct link frame interval to the relay link frame interval.

22. The apparatus of claim 19, wherein the transmitter comprises:

a frame constructor for constructing a frame using subframes of signals to be transmitted; and

a resource mapper for mapping the subframes of the constructed frame to resources allocated to bursts of the respective links.

23. The apparatus of claim 19, wherein the receiver comprises:

a resource demapper for extracting subframes allocated to the respective bursts of the received signals; and

a frame extractor for extracting subframes of the links from the extracted subframes.

24. A wireless communication system, comprising:

means for constructing a direct link subframe to communicate in a direct link between a Base Station (BS) and a Relay Station (RS) or a Mobile Station (MS) during a first interval of the subframe; and

means for constructing a direct link subframe to communicate in a direct link between the BS and an MS, and a relay link subframe to communicate in a relay link between the RS and an MS during a second interval of the subframe.

25. The wireless communication system of claim 24, wherein the direct link subframe and the relay link subframe in the second interval are constructed through a spatial multiplexing in the same frequency band.

26. A Base Station (BS) in a wireless communication system, comprising:

means for setting a direct link frame interval for providing service to a Relay Station (RS) or a Mobile Station (MS) in a direct link;

means for designating a start point of a relay link frame for providing service between the RS and the MS according to a Broadcast Channel (BCH) transmission interval in the direct link frame;

means for sending start point information of the relay link frame to the RS; and

means for communicating with one of the RS and an MS according to the direct link frame construction scheme.

27. A wireless communication system, comprising:

means for constructing a direct link subframe for a Base Station (BS) to send a signal to a Relay Station (RS) or a Mobile Station (MS) in a direct link during a first interval of the frame;

means for constructing a relay link subframe for the RS to send a signal to the MS in a relay link during a second interval of the frame;

means for constructing a direct link subframe for the BS to send a signal to the MS in a direct link during a third interval of the frame;

means for constructing a direct link subframe for one of the RS and the MS to send a signal to the BS in a direct link during a fourth interval of the frame; and

means for constructing a relay link subframe for the MS to send a signal to the RS in a relay link during a fifth interval of the frame.

28. A Base Station (BS) of a wireless communication system, comprising:

means for setting a direct link frame interval for communicating with a Relay Station (RS) or a Mobile Station (MS) in a direct link;

means for setting a relay link frame interval for communicating between the RS and the MS in relay link;

means for constructing a frame by time-dividing the frame interval to a certain number of intervals and allocating the intervals to a direct link frame or a relay link frame; and

means for sending the frame construction information to the RS and the MS.