Method and apparatus for scheduling packets in an orthogonal frequency division multiple access (OFDMA) system
View Patent ↗A method and apparatus for scheduling packets in an orthogonal frequency division multiple access (OFDMA) system is provided. More particularly, the presently described embodiments relate to a scheduling system whereby packets are prioritized based on packet delay information. The system also handles poor geometry users in an improved manner.
1. A method for scheduling packets in an orthogonal frequency division multiple access (OFDMA) system, the method comprising:
determining whether a packet corresponds to a poor geometry user;
segmenting the packet into smaller packets if the packet belongs to a poor geometry user;
scheduling each segmented packet for transmission independently;
if the packet is not segmented, determining if the packet is to be retransmitted;
retransmitting the packet if it is to be retransmitted;
if the packet is not to be retransmitted, determining if the packet is subject to a persistent assignment;
if the packet is subject to persistent assignment, transmitting the packet using persistently assigned resources in a persistently assigned format; and,
if the packet is not subject to persistent assignment, prioritizing transmission of the packet based on packet delay information, wherein the prioritizing transmission comprises tracking a number of non-persistent assignment messages in an interlace; and
transmitting the packet if the number of non-persistent assignment messages for the interlace is equal to a preset value.
2. The method as set forth in claim 1 wherein the transmitting of the smaller segmented packets comprises prioritizing the transmission based on packet delay information.
3. The method as set forth in claim 1 wherein retransmitting comprises retransmitting through a physical layer.
4. The method as set forth in claim 1 further comprising determining whether a user should be added to a persistent assignment list.
5. The method as set forth in claim 1 further comprising determining whether a maximum number of packets have been assigned a priority based on delay.
6. The method as set forth in claim 1 wherein the packet delay parameters are based on delay experienced by users for which packets are not being retransmitted or persistently assigned.
7. A system for scheduling packets in an orthogonal frequency division multiple access (OFDMA) system, the system comprising:
means for determining if a packet is to be retransmitted;
means for retransmitting the packet if it is to be retransmitted;
means for if the packet is not to be retransmitted, determining if the packet is subject to a persistent assignment;
means for if the packet is subject to persistent assignment, transmitting the packet using persistently assigned resources in a persistently assigned format; and,
means for if the packet is not subject to persistent assignment, prioritizing transmission of the packet based on packet delay information, wherein the prioritizing transmission comprises tracking a number of non-persistent assignment messages in an interlace; and
means for transmitting the packet if the number of non-persistent assignment messages for the interlace is equal to a preset value.