Method and apparatus for data transportation and synchronization between MAC and physical layers in a wireless communication system

• US 6,683,866 B1
• Filed: 10/29/1999
• Issued: 01/27/2004
• Est. Priority Date: 10/29/1999
• Status: Expired due to Term

• Current Assignee: Quarterhill Inc. (f/k/a Wi-LAN Inc.)
• Original Assignee: Ensemble Communications
• Inventors: Samad, Gary Lee Jr., Stanwood, Kenneth L., Behar, Jacques
• Primary Examiner(s): Olms, Douglas
• Assistant Examiner(s): Wilson, Robert W.
• Application Number:
  US09/430,379
• Time in Patent Office: 1,551 Days
• Field of Search: 370/337, 370/338, 370/350, 370/503, 370/473, 370/474, 370/465, 370/468
• US Class Current: 370/350
• CPC Class Codes: H04L 69/324 in the data link layer [OSI layer 2], e.g. HDLC
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04W 80/02 Data link layer protocols

Abstract

The present invention is a novel method and apparatus for efficiently transporting and synchronizing data between the Media Access Control (MAC) and physical communication protocol layers in a wireless communication system. Depending on the length of the MAC packet to be transported, the present invention either fragments or concatenates the MAC packet when mapping to the physical layer. When a MAC packet is too long to fit in one TC/PHY packet, the MAC packet is fragmented and the resultant multiple TC/PHY packets are preferably transmitted back-to-back within the same TDD frame. When a MAC packet is shorter than a TC/PHY packet, the next MAC packet is concatenated with the current MAC packet into a single TC/PHY packet unless an exception applies (e.g., a change in CPE on the uplink or a change in modulation on the downlink). When an exception applies, the next MAC packet is started on a new TC/PHY packet following either a CTG or MTG.

Claims

1. A method of synchronizing and transporting data in a wireless communication system, wherein the wireless communication system includes a plurality of customer premise equipment (CPE) in communication with associated and corresponding base stations, and wherein the base stations maintain uplink and downlink sub-frame maps representative of bandwidth allocations in uplink and downlink communication links, and wherein the base stations each include an associated and corresponding media access control (MAC) having a plurality of MAC data messages, and wherein the MAC transports a MAC data message through a MAC data packet that is mapped to at least one TC/PHY packet in a layered data transport architecture, the method comprising the steps of:

(a) obtaining a MAC data packet;

(b) determining whether there are sufficient available bits in a first TC/PHY packet to map the MAC data packet obtained in step (a) into the first TC/PHY packet;

(c) if sufficient bits are determined to be available in step (b), proceeding to step (d), else fragmenting the obtained MAC data packet and mapping a first fragment into the first TC/PHY packet, and then mapping remaining fragments into successive TC/PHY packets, and then returning to step (a);

(d) mapping the obtained MAC data packet into the first TC/PHY packet;

(e) determining whether there are remaining available bits in the first TC/PHY packet;

(f) if sufficient bits are determined to be remaining in step (e), proceeding to step (g), else returning to step (a);

(g) determining whether there is a change in modulation on the downlink;

(h) if a change in modulation is determined in step (g), mapping a first MAC packet having a new modulation into a new TC/PHY packet following an MTG, else proceeding to step (i);

(i) determining whether there is a change in CPE on the uplink;

(j) if a change in modulation is determined in step (i), mapping a first MAC packet of a next CPE into a new TC/PHY packet following a CTG, else proceeding to step (k);

(k) mapping a next MAC packet, if one exists, within the first TC/PHY packet; and

(l) returning to step (b).

2. The method of synchronizing and transporting data of claim 1, wherein the MAC data packets comprise a MAC header and a MAC payload having a length of n bits.

3. The method of synchronizing and transporting data of claim 2, wherein n is variable.

4. The method of synchronizing and transporting data of claim 2, wherein n is fixed.

5. The method of synchronizing and transporting data of claim 2, wherein the MAC header further comprises a fragmentation control field, and wherein the fragmentation control field contains information regarding fragmentation of the MAC data message.

6. The method of synchronizing and transporting data of claim 2, wherein the TC/PHY packet further comprises a TC/PHY payload and a TC/PHY header.

7. The method of synchronizing and transporting data of claim 6, wherein the TC/PHY header further comprises a position field, and wherein the position field provides information regarding the byte position of the MAC header, if present, within the TC/PHY payload.

8. The method of synchronizing and transporting data of claim 1, wherein the mapping of the MAC data packet into the TC/PHY packet of step (d) comprises encoding the TC/PHY packet.

9. The method of synchronizing and transporting data of claim 8, wherein the TC/PHY packet is encoded using Reed-Solomon coding.

17. The method of synchronizing and transporting data of claim 6, wherein the TC/PHY header further comprises a header present field, and wherein data in the header present field indicates a presence or absence of a MAC header within the TC/PHY payload.

18. The method of synchronizing and transporting data of claim 17, wherein the header present field of the TC/PHY header comprises a bit that is set to a logical one only when a MAC header is present within the TC/PHY payload.

10. An apparatus for synchronizing and transporting data in a wireless communication system, wherein the wireless communication system includes a plurality of customer premise equipment (CPE) in communication with associated and corresponding base stations, and wherein the base stations maintain uplink and downlink sub-frame maps representative of bandwidth allocations in uplink and downlink communication links, and wherein the base stations each include an associated and corresponding media access control (MAC) having a plurality of MAC data messages, and wherein the MAC transports a MAC data message through a MAC data packet mapped to at least one TC/PHY packet in a layered data transport architecture, comprising:

(a) means for obtaining a MAC data packet;

(b) means for determining whether there are sufficient available bits in the TC/PHY packet to map the MAC data packet into a TC/PHY packet;

(c) means for fragmenting the MAC data packet;

(d) means for mapping the MAC data packet into the TC/PHY packet;

(e) means for determining whether there are remaining available bits in the TC/PHY packet;

(f) means for determining whether there is a change in modulation on the downlink;

(g) means for mapping a first MAC packet of a new modulation into a new TC/PHY packet following a MTG;

(h) means for determining whether there is a change in CPE on the uplink; and

(i) means for mapping a first MAC packet of a next CPE into a new TC/PHY packet following a CTG.

11. A computer program executable on a general purpose computing device, wherein the program is capable of synchronizing and transporting data in a wireless communication system, and wherein the wireless communication system includes a plurality of customer premise equipment (CPE) in communication with associated and corresponding base stations, and wherein the base stations maintain uplink and downlink sub-frame maps representative of bandwidth allocations in uplink and downlink communication links, and wherein the base stations each include an associated and corresponding media access control (MAC) having a plurality of MAC data messages, and wherein the MAC transports a MAC data message through a MAC data packet mapped to at least one TC/PHY packet in a layered data transport architecture, comprising:

(a) a first set of instructions for obtaining a MAC data packet;

(b) a second set of instructions for determining whether there are sufficient available bits in the TC/PHY packet to map the MAC data packet into a TC/PHY packet;

(c) a third set of instructions for fragmenting the MAC data packet and for mapping the fragmented MAC packets into TC/PHY packets if there are not sufficient available bits in the TC/PHY packet to map the MAC data packet;

(d) a fourth set of instructions for mapping the MAC data packet into the TC/PHY packet;

(e) a fifth set of instructions for determining whether there are remaining available bits in the TC/PHY packet;

(f) a sixth set of instructions for determining whether there is a change in modulation on the downlink;

(g) a seventh set of instructions for mapping a first MAC packet of a new modulation into a new TC/PHY packet following a MTG;

(h) an eighth set of instructions for determining whether there is a change in CPE on the uplink;

(i) a ninth set of instructions for mapping a first MAC packet of a next CPE into a new TC/PHY packet following a CTG; and

(j) a tenth set of instructions for mapping a next MAC data packet, if one exists, within the TC/PHY packet.

12. A method of re-synchronizing data in a wireless communication system, wherein the wireless communication system includes a plurality of customer premise equipment (CPE) in communication with associated and corresponding base stations having uplink and downlink communication links with the plurality of CPEs, and wherein the base stations maintain uplink and downlink sub-frame maps representative of bandwidth allocations in the uplink and downlink communication links, and wherein the base stations each include an associated and corresponding media access control (MAC) having a plurality of MAC data messages, and wherein the MAC transports a MAC data message through a MAC data packet that is mapped to at least one TC/PHY packet in a layered data transport architecture, and wherein each TC/PHY packet includes a header present field, and wherein at least one of the communication links may be intermittently disrupted during data transmission, the method comprising the steps of:

(a) detecting a disruption of a communication link during data transmission;

(b) reestablishing the communication link that was detected as disrupted at step (a);

(c) receiving a TC/PHY packet;

(d) detecting the header present field of the TC/PHY packet received at step (c), and if data in the header present field indicates the presence of a particular kind of data within a payload of said TC/PHY packet, proceeding to step (e), else returning to step (c); and

(e) resuming data transmission on the disrupted communication link, wherein at most only one MAC data message is lost after reestablishing the communication link in step (b).

13. The re-synchronizing method of claim 12, wherein in step (d) the particular kind of data indicated by data in the packet header field is data that begins a message that is conveyed in payloads of one or more TC/PHY packets.

14. The re-synchronizing method of claim 13, wherein the message conveyed in payloads of one or more TC/PHY packets is a variable-length MAC packet.

15. The re-synchronizing method of claim 14, wherein the particular kind of data is a beginning of a MAC packet header.

16. The re-synchronizing method of claim 15, wherein the header present field is a single bit, and if set to logical “

one”

indicates a presence in the payload of the TC/PHY packet of a beginning of a MAC packet header.