Method for minimizing time critical transmit processing for a personal computer implementation of a wireless local area network adapter
View Patent ↗A personal computer's (PC) microprocessor is used to provide both the physical layer (PHY) and media access control (MAC) processing functions required to implement a wireless local area network (WLAN) adapter. This technique uses the microprocessor within the personal computer to pre-compute the time critical PHY waveforms required to respond to received packets. For instance, the acknowledge (ACK) waveform required to respond to a received WLAN packet is pre-computed and stored in the PC memory. Upon receipt of a valid packet, the samples of the ACK waveform are transferred from the PC memory to a digital to analog converter (DAC). The DAC generates the transmit waveform required for the radio modulator. By pre-computing the transmit waveform samples, the required loading on the PC microprocessor is reduced during time critical periods.
1. A method for the reduction of transmit processing in response to a received packet in a communications system comprising:
generating a plurality of transmit control frames for responding to received packets;
generating transmit waveform samples from the generated plurality of transmit control frames;
storing the transmit waveform samples in buffer memory;
receiving a packet;
determining a transmit waveform sample associated with the received packet; and
transmitting the determined transmit waveform samples.
2. A method as in claim 1 , wherein the generated transmit control frame contains data which is learned over time from the communications system.
3. A method as in claim 1 , wherein the generated transmit control frame contains a duration field.
4. A method as in claim 3 , wherein the duration field is set to a maximum length packet exchange for a specific data rate.
5. A method as in claim 1 , wherein the generated transmit control frames contain power management mode information.
6. A method as in claim 1 , wherein the generation of the transmit waveform samples varies by data rate.
7. A method as in claim 2 , wherein the learned data are transmit addresses of received packets.
8. A method as in claim 1 , in which the communications system is wireless.
9. A method as in claim 1 , in which the communications system is IEEE 802.11.
10. A method as in claim 1 , in which the communications system is Bluetooth.
11. A method as in claim 1 , in which the communications system is IEEE 802.15.
12. A method for the reduction of transmit processing in response to a received packet in a communications system comprising the steps of:
maintaining in memory a plurality of transmit waveform samples;
generating new transmit waveform samples in response to detection of new transmit addresses in the system;
saving the new transmit samples to the memory;
indexing the memory based on receiving a specific transmit address in a received packet;
determining an appropriate transmit waveform sample from the indexed memory; and
transmitting the appropriate transmit waveform sample.
13. A method as in claim 12 , wherein the transmit waveform samples vary by data rate.
14. A method as in claim 12 , wherein the indexing of memory varies by data rate.
15. A method as in claim 12 , in which the communications system is wireless.
16. A method as in claim 12 , in which the communications system is IEEE 802.11.
17. A method as in claim 12 , in which the communications system is IEEE 802.15.