Wireless Communication Systems

Abstract

A wireless communication method in a system in which subscriber stations are each operable for communication with a base station is provided. The base station is capable of performing simultaneous communications with a plurality of the subscriber stations simultaneously by exchange of packets each conforming with a layered protocol of said system. The packets include a first portion for defining physical layer (PHY) parameters and a second portion for defining media access layer (MAC) parameters. Furthermore, communications between the subscriber stations and the base station are performed wholly or partly through at least one relay station. In this system, the method includes, in the relay station, receiving a plurality of packets from the subscriber stations, detecting the second portion of each of the packets, combining the detected second portions to form a second portion of at least one new packet, and transmitting the new packet to the base station.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and its advantages, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which:

FIG. 1 shows protocol layering in accordance with IEEE 802.16;

FIG. 2 shows the relationship between CID, SFID and QoS in an IEEE 802.16 network;

FIG. 3 shows a packet format capable of being used in an IEEE 802.16 network;

FIG. 4 shows a generic MAC header of a packet as set forth in the IEEE 802.16 specification;

FIG. 5 illustrates a simple relay protocol in a multi-hop wireless communication system;

FIG. 6 illustrates the relay protocol employed in a particular embodiment of the present invention;

FIG. 7 is a flowchart of processing in an relay station to combine MAC PDUs;

FIG. 8 shows a first method of combining MAC PDUs;

FIG. 9 shows a second method of combining MAC PDUs;

FIG. 10 shows a third method of combining MAC PDUs; and

FIG. 11 is a flowchart of processing in a base station.

DETAILED DESCRIPTION

An embodiment of the present invention will now be described with reference to FIGS. 6-11, using an IEEE 802.16 network as an example. In this embodiment, an algorithm is proposed by which the RS can combine the packets received from the communication devices connected to itself, forming one or more new packets (combined packets), and send the combined packets to the BS (or to an upstream RS), thus decreasing the overhead and collision of packet transmission. This relay protocol is schematically shown in FIG. 6. There are various possible ways of combining received packets, as will now be explained.

1. Operations in RS

Referring to FIG. 7, the following operations take place on the RS side after the RS receives multiple packets from the connected radio devices.

(i) RS detaches the MAC PDUs from the packets received. If the CRC is available in a MAC PDU, then RS will check the CRC and discard the MAC PDUs with CRC error.

(ii) In terms of the types or the QoS level of the received MAC PDUs, the RS then categorizes the correctly received MAC PDUs. The purpose of this step is to further decrease the overhead by combining MAC PDUs, and to make the QoS management convenient in RS. For example, the received packets may include bandwidth requests; the RS can group the bandwidth requests and then send one bandwidth-request MAC PDU to BS as an aggregation bandwidth request for all received requests. RS also can group MAC PDUs with same latency requirement (QoS), and then it can decide when to send the grouped PDUs. Since an RS can also combine all the received MAC PDUs without considering their types, this step is optional.

(iii) The RS combines the MAC PDUs within same category, and then adds its MAC header and CRC into the combined MAC PDU. One combination method is firstly removing CRC sequences in the received MAC PDUs, and then linking the individual MAC PDUs, as shown in FIG. 8. Another method is using a new MAC PDU to replace the grouped MAC PDUs, as illustrated in FIG. 9. For example, in an OFDMA wireless system, RS may use one bandwidth request to apply for bandwidth for a group of devices. Another method is firstly extracting the payload from the received MAC PDUs, and then combining these payloads in a new MAC PDU, as depicted in FIG. 10. In this case, the new MAC header should describe how to combine the payloads. In all above methods, if necessary, a previously configured CID, identifying the connection between RS and BS, and other information will be added into the new MAC PDU.

(iv) Finally, the RS delivers the MAC PDU to PHY layer to add PHY header and other information, and transmit this MAC PDU.

2. Operations in BS

Referring to FIG. 11, the following operations take place on the BS side after the BS receives the new packet having the combined MAC PDU from the RS:

(i) BS checks the CRC (if available) for the received packet from RS. BS will discard the packets with CRC error;

(ii) BS checks the CID (if available) for the received packet from RS. BS will discard the packet with unknown CID;

(iii) BS decodes the MAC PDU, or fragments the linked MAC PDUs if present (FIG. 8) and decodes them.

Although the above description concerns the processing in a single RS and BS, other RSs may be present in the network. In this case, in relation to each other RS, the first RS may act like the BS in the above explanation. Each other RS will serve its own set of SSs and combine the packets received from those SSs in the same manner as explained above for the first RS.

Particular embodiments of the present invention may provide one or more of the following effects:

Define a protocol for an RS to process the received packets.

Minimize the PHY overhead by classifying and combining received packets in RS.

Decreases the collision probability for the contention style packets between RS and BS.

Embodiments of the present invention may be implemented in hardware, or as software modules running on one or more processors, or on a combination thereof. That is, those skilled in the art will appreciate that a microprocessor or digital signal processor (DSP) may be used in practice to implement some or all of the functionality of the RS or BS in embodiments of the present invention. It is also possible to provide each SS with some or all of the functionality of the RS. The invention may also be embodied as one or more device or apparatus programs (e.g. computer programs and computer program products) for carrying out part or all of any of the methods described herein. Such programs embodying the present invention may be stored on computer-readable media, or could, for example, be in the form of one or more signals. Such signals may be data signals downloadable from an Internet website, or provided on a carrier signal, or in any other form.

Although the present invention has been described with several embodiments, a myriad of changes, variations, alterations, transformations, and modifications may be suggested to one skilled in the art, and it is intended that the present invention encompass such changes, variations, alterations, transformations, and modifications as fall within the scope of the appended claims.

Claims

1. A wireless communication method in a system in which subscriber stations are each operable for communication with a base station, the base station being capable of performing simultaneous communications with a plurality of the subscriber stations simultaneously by exchange of packets each conforming with a layered protocol of said system, the packets comprising a first portion for defining physical layer (PHY) parameters and a second portion for defining media access layer (MAC) parameters, and communications between the subscriber stations and the base station being performed wholly or partly through at least one relay station, the method comprising steps of, in the relay station: receiving a plurality of packets from the subscriber stations;detecting the second portion of each of the packets;combining the detected second portions to form a second portion of at least one new packet; andtransmitting the new packet to the base station.

2. The method according to claim 1, wherein the second portion of each packet includes error-checking information, and said detecting step comprises checking the error-checking information of packets received from the subscriber stations and discarding any packets thereby found to have been incorrectly received.

3. The method according to claim 2, wherein the combining step comprises removing the error-checking information from the second portion of each received packet and linking the remainder of each second portion to form the second portion of the new packet.

4. The method according to claim 1, wherein the combining step comprises forming the new packet with a new second portion representing the aggregate contents of the second portions of the received packets.

5. The method according to claim 1, wherein the combining step comprises extracting a payload, if any, from the second portion of each of the received packets and combining the payloads so extracted in a new second portion of the new packet.

6. A wireless communication method in a system in which subscriber stations are each operable for communication with a base station, the base station being capable of performing simultaneous communications with a plurality of the subscriber stations simultaneously by exchange of packets each conforming with a layered protocol of said system, the packets comprising a first portion for defining physical layer (PHY) parameters and a second portion for defining media access layer (MAC) parameters, and communications between the subscriber stations and the base station being performed wholly or partly through at least one relay station, the method comprising steps of, in the relay station: receiving a plurality of packets from the subscriber stations;detecting the second portion of each of the packets;categorizing the detected second portions of the received packets;combining the detected second portions to form a second portion of a new packet for each category used in said categorizing step; andtransmitting each new packet to the base station.

7. The method according to claim 6, wherein the categorizing step is performed based on type or service level information contained in each second portion of the received packets.

8. The method according to claim 7, wherein the type information includes a designation of the packet as a bandwidth request from a subscriber station to the base station.

9. The method according to claim 7, wherein received packets having the same service level information are categorized together for forming a new packet.

10. The method according to claim 9, wherein the transmitting step includes transmitting each new packet to the base station in order of priority based on the service level information.

11. The method according to claim 6, wherein the first portion is a PHY header and the second portion is a MAC protocol data unit (PDU) including a MAC header.

12. The method according to claim 11, wherein the combining step comprises providing the new packet with a MAC header identifying the relay station.

13. The method according to claim 11, wherein said combining step comprises forming the MAC PDU of the new packet and delivering the same to a PHY layer of the relay station to add the PHY header.

14. The method according to claim 12, wherein the base station performs communications by monitoring active connections with subscriber stations and the relay station, each such connection having a connection ID, and the relay station includes the connection ID of its connection with the base station within the MAC header of the new packet.

15. The method according to claim 6, further comprising, in the base station, receiving the or each new packet sent from the relay station and decoding the second portion thereof.

16. The method according to claim 14, further comprising, in the base station, checking the connection IDs of received packets and discarding any packet having an unknown connection ID.

17. The method according to claim 15, wherein the combining step comprises removing the error-checking information from the second portion of each received packet and linking the remainder of each second portion to form the second portion of the new packet, wherein said decoding step in the base station comprises fragmenting the linked second portions contained in the new packet sent from the relay station.

18. The method according to claim 6, wherein the system comprises a further relay station arranged for communication with said relay station, the further relay station performing the same steps as said relay station in relation to further subscriber stations, the receiving step in said relay station including receiving one or more packets from said further relay station.

19. The method according to claim 6, wherein at least some of the subscriber stations are mobile stations.

20. A wireless communication system in which subscriber stations are each operable for communication with a base station, the base station being capable of performing simultaneous communications with a plurality of the subscriber stations simultaneously by exchange of packets each conforming with a layered protocol of said system, the packets comprising a first portion for defining physical layer (PHY) parameters and a second portion for defining media access layer (MAC) parameters, and communications between the subscriber stations and the base station being performed wholly or partly through at least one relay station, wherein the relay station comprises: a receiver arranged to receive a plurality of packets from the subscriber stations;a detector arranged to detect the second portion of each of the packets;a processor arranged to combine the detected second portions to form a second portion of at least one new packet; anda transmitter for transmitting the new packet to the base station.

21. A relay station for use in a wireless communication method in a system in which subscriber stations are each operable for communication with a base station, the base station being capable of performing simultaneous communications with a plurality of the subscriber stations simultaneously by exchange of packets each conforming with a layered protocol of said system, the packets comprising a first portion for defining physical layer (PHY) parameters and a second portion for defining media access layer (MAC) parameters, and communications between the subscriber stations and the base station being performed wholly or partly through the relay station, the relay station comprising: a receiver for receiving a plurality of packets from the subscriber stations;a detector for detecting the second portion of each of the packets;a processor for combining the detected second portions to form a second portion of at least one new packet; anda transmitter for transmitting the new packet to the base station.

22. The relay station according to claim 21, wherein the second portion of each packet includes error-checking information, and said detector is arranged to check the error-checking information of packets received from the subscriber stations and discard any packets thereby found to have been incorrectly received.

23. The relay station according to claim 21, wherein the processor is arranged to remove the error-checking information from the second portion of each received packet and link the remainder of each second portion to form the second portion of the new packet.

24. The relay station according to claim 21, wherein the processor is operable for forming the new packet with a new second portion representing the aggregate contents of the second portions of the received packets.

25. The relay station according to claim 21, wherein the combining means is arranged to extract a payload, if any, from the second portion of each of the received packets and to combine the payloads so extracted in a new second portion of the new packet.

26. A relay station for use in a wireless communication method in a system in which subscriber stations are each operable for communication with a base station, the base station being capable of performing simultaneous communications with a plurality of the subscriber stations simultaneously by exchange of packets each conforming with a layered protocol of said system, the packets comprising a first portion for defining physical layer (PHY) parameters and a second portion for defining media access layer (MAC) parameters, and communications between the subscriber stations and the base station being performed wholly or partly through the relay station, the relay station comprising: a receiver for receiving a plurality of packets from the subscriber stations;a detector for detecting the second portion of each of the packets;a processor for categorizing the detected second portions of the received packets, and combining the detected second portions according to their categories to form a new packet for each category; anda transmitter for transmitting the new packets to the base station.

27. The relay station according to claim 26, wherein the processor is responsive to type or service level information contained in each second portion of the received packets.

28. The relay station according to claim 27, wherein the type information includes a designation of the packet as a bandwidth request from a subscriber station to the base station.

29. The relay station according to claim 27, wherein received packets having the same service level information are categorized together for forming a new packet.

30. The relay station according to claim 29, wherein the transmitter is arranged to transmit each new packet to the base station in order of priority based on the service level information.

31. The relay station according to claim 26, wherein the first portion of each packet is a PHY header and the second portion is a MAC protocol data unit (PDU) including a MAC header.

32. The relay station according to claim 31, wherein the processor is arranged to provide the new packet with a MAC header identifying the relay station.

33. The relay station according to claim 32, wherein the base station performs communications by monitoring active connections with the subscriber station and the relay station, each such connection having a connection ID, and the processor is arranged to include the connection ID of its connection with the base station within the MAC header of the new packet.

34. A base station for use in a wireless communication method in a system in which subscriber stations are each operable for communication with the base station, the base station being capable of performing simultaneous communications with a plurality of the subscriber stations simultaneously by exchange of packets each conforming with a layered protocol of said system, the packets comprising a first portion for defining physical layer (PHY) parameters and a second portion for defining media access layer (MAC) parameters, and communications between the subscriber stations and the base station being performed wholly or partly through at least one relay station which receives a plurality of packets from the subscriber stations, detects the second portion of each of the packets, combines the detected second portions to form a second portion of at least one new packet, and transmits the new packet to the base station; wherein the base station comprises: a receiver for receiving the or each new packet sent from the relay station; anda decoder for decoding the second portion of the new packet.

35. The base station according to claim 34, wherein the second portion of each packet includes error-checking information, and said decoder includes means for checking the error-checking information of the or each new packet sent from the relay station, and discarding any packet found to have been incorrectly received.

36. The base station according to claim 34, wherein the second portion of every packet contains a connection ID identifying an active connection in the system, and the base station monitors connection IDs of its own active connections.

37. The base station according to claim 36, wherein said decoder checks the connection IDs of received packets and discards any packet having an unknown connection ID.

38. The base station according to claim 34, wherein the new packet sent from the relay station includes linked second portions of the packets received from the plurality of subscriber station, and the decoder is arranged to fragment said linked second portions.