Method for Mitigating Adverse Processor Loading in a Personal Computer Implementation of a Wireless Local Area Network Adapter

Abstract

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 polling mechanism associated with the power save (PS) functionality of WLAN protocol to relieve networking stress on the host processing system. It does this while maintaining networking integrity and packet delivery. The WLAN protocol polling mechanism is used to briefly inhibit the transfer of packets from the WLAN access point (AP) during peak periods of network traffic and / or host processor loading. Because the modulation, demodulation, and MAC functions, typically implemented in dedicated hardware on existing adapters are implemented in software running on the host PC microprocessor, other host system processes and applications can interfere with these time critical functions. Conversely, latency introduced by WLAN specific processing tasks during peak periods of network traffic may cause unacceptable delays to the other processes and applications requiring microprocessor attention. In addition to its primary stated purpose of allowing WLAN mobile stations to save power, this technique will use power save polling as a method for controlling delivery of network packets when the host is heavily loaded or when peak interrupt latencies make reliable packet delivery difficult or impossible.

Description

[0001]This invention relates to electronic communications systems and more particularly to a system for enabling a computer to transmit and receive information over a packet based wireless communications link. This invention claims the benefit of priority to U.S. Provisional Patent Application No. 60 / 397,912 filed Jul. 23, 2002.BACKGROUND OF THE INVENTION[0002]The host microprocessor of personal computers (PC) has been used to provide the signal processing functions required to implement wire line analog communications functions for some time. The modulator demodulator (MODEM) functions required to implement existing wire line standards were historically implemented in software running on dedicated signal processors on the modem hardware. With the advent of more and more powerful personal computers it became possible to implement much of the processing software on the host processor within the PC. Using the host processor instead of dedicated signal processors greatly reduces the co...

AI Technical Summary

Benefits of technology

[0006]A primary objective of the present invention is to provide a technique for enabling a personal computer to transmit and receive information over a packet based wireless communications link at very low cost by using the personal computers central processing unit (CPU) to perform most of the communications link processing.

[0007]A secondary objective is to use the polling mechanism associated with the power save functionality in the WLAN protocol to control delivery of network packets, when the host CPU is heavily loaded or when interrupt latencies make reliable packet delivery difficult or impossible, in such a way as to minimize the processing load on the host CPU so that it can be used simultaneously for both wireless packet data and other desktop applications.

Problems solved by technology

On the surface it would appear that the processing required by the WLAN adapter would make the load on the PC host microprocessor prohibitive.

However, the mechanisms used in this technique (PS mode) will allow a mobile station, whose host processor loading becomes excessive, to defer packet reception until such time as the processor becomes available again.

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