An Universal MAC/PHY Interface for Different WLAN Standards
Wireless LAN (WLAN) is widely considered to play a major role in wireless multimedia communications. Two competing standards: IEEE802.11a and HIPERLAN/2 will dominate WLAN market. These two standards have a similar physical layer that is based on Orthogonal Frequency Division Multiplexing (OFDM) technology, but the Medium Access (MAC) layers are different. Mitsubishi Electric Corp. is currently developing the chipset for WLAN. Mitsubishi Electric Corp. has strong capabilities in the radio front end as well as OFDM implementations. The project here is to develop a universal interface between MAC and Physical (PHY) layers. This allows the reuse more of PHY components in both IEEE802.11a and HIPERLAN/2 products, and helps Mitsubishi Electric Corp.'s position in WLAN chip market. In this way several WLAN manufactures could use the Mitsubishi Electric Corp. PHY chipset and connect any of the WLAN MAC layers to this PHY chipset.
Background & Objective: Two different incompatible WLAN standards operating in the same 5GHz band - IEEE802.11a and HIPERLAN/2 will cause interferences and other problems. From the end user perspective, the end user is forced to make a standard choice, and no roaming is possible. From the manufacture perspective, two sets of different chipsets have to be made for the WLAN market. Now, IEEE 802.11 working group is developing algorithms that allow inter-working between these two standards. The manufactures are trying to develop a single universal device that is IEEE802.11a and HIPERLAN/2 compliant.
Technical Discussion: Since IEEE802.11a and HIPERLAN/2 have quite similar PHY layers and much different MAC layers. The goal of the universal MAC/PHY interface is to try to reuse more PHY components in both 802.11a and HIPERLAN/2 products. The basic idea is that the MAC/PHY interface will include two training sequence generators. One is for both 802.11a and HIPERLAN/2; the other is a short training sequence generator for only HIPERLAN/2. The interface will also contains an initialization procedure that can initialize both 802.11a MAC data and HIPERLAN/2 MAC data unit for physical transmission. In addition, the convolution en/decoder in PHY layer has to be designed to offer the code rates of 1/2, 9/16, 2/3,3/4, and extra puncture scheme for HIPERLAN/2.
Contact: Philip Orlik
Technology Area: Networks
Modification Date: September 12, 2007
