System and method for per frame overhead reduction in air interface for OFDMA systems
An OFDMA system having a reduced overhead, particularly suitable for narrow bandwidth systems, in which uplink and downlink map messages have reduced length for efficiency.
1. A non-transient computer-readable medium for causing a processor of a base station in an OFDMA system to perform the method of reducing a size of a Media Access Control (MAC) layer message according to the IEEE 802.16 standard between the base station and the OFDMA system, the method comprising:
transmit to remote stations in communication with the base station reduced-length downlink and uplink map MAC messages,
wherein the length of a header of said reduced-length uplink and downlink map MAC message is no more than 16 bits and wherein the reduced-length downlink message includes a header consisting of a length field and a header check sequence (HCS).
2. The non-transient computer-readable medium according to claim 1 , wherein the reduced-length uplink map message includes a header consisting essentially of a first bit indication of an uplink header, a length field, and a header check sequence (HCS).
3. The non-transient computer-readable medium according to claim 1 , wherein the reduced-length uplink and downlink map messages each include a cyclic redundancy check (CRC) field comprising no more than 8 bits.
4. The non-transient computer-readable medium according to claim 1 , wherein the reduced-length downlink map message comprises one bandwidth allocation information element (IE) per modulation and forward error correction scheme (“FEC Code”) having no more than 8 bits, said bandwidth allocation IE identifying a two dimensional allocation by indicating the number of slots in the allocation.
5. The non-transient computer-readable medium according to claim 1 , wherein the reduced-length uplink map message includes a data burst information element (IE), wherein the data burst IE consists essentially of a connection identifier (CID) having no more than 16 bits, an uplink interval usage code (UIUC) having no more than 4 bits, and a duration having no more than 10 bits.
6. The non-transient computer-readable medium according to claim 1 , wherein the reduced-length uplink map message includes a CDMA allocation information element (IE), wherein the CDMA allocation IE consists essentially of an uplink interval usage code (UIUC) having no more than 4 bits, a duration having no more than 4 bits, a frame number index having no more than 4 bits, a ranging code having no more than 8 bits, and a bandwidth request mandatory indication code.
7. The non-transient computer-readable medium according to claim 1 , wherein the reduced-length uplink map message includes a power control information element (IE), wherein the power control IE consists essentially of a connection identifier (CID) having no more than 16 bits, an uplink interval usage code (UIUC) having no more than 4 bits, and a power control field having no more than 8 bits.
8. The non-transient computer-readable medium according to claim 1 , wherein the reduced-length downlink map includes a media access control (MAC) management message (MMM) consisting essentially of a frame number having no more than 16 bits.
9. The non-transient computer-readable medium according to claim 1 , wherein the reduced-length uplink map does not include a media access control (MAC) management message (MMM).
10. A method of reducing a size of a Media Access Control (MAC) layer message according to the IEEE 802.16 standard between the base station and an OFDMA system, the method comprising:
transmitting to remote stations in communication with the base station reduced-length downlink and uplink map MAC messages,
wherein the length of a header of said reduced-length uplink and downlink map MAC message is no more than 16 bits, and wherein the reduced-length downlink message includes a header consisting of a length field and a header check sequence (HCS), and
wherein a channel bandwidth for the OFDMA system is less than or equal to 1.25 MHz.
11. The method of claim 10 , wherein a per-frame bandwidth required for transmitting the reduced-length downlink and uplink map messages is less than or equal to approximately 10% of the channel bandwidth.