WATMnet: a prototype wireless ATM system for multimedia personal communication

C&C Res. Labs., NEC Res. Inst., Princeton, NJ
IEEE Journal on Selected Areas in Communications (Impact Factor: 4.14). 02/1997; DOI: 10.1109/49.553680
Source: IEEE Xplore

ABSTRACT A prototype microcellular wireless asynchronous transfer mode
network (WATMnet) capable of providing integrated multimedia
communication services to mobile terminals is described in this paper.
The experimental system's hardware consists of laptop computers (NEC
Versa-M) with WATMnet interface cards, multiple VME/i960 processor-based
WATMnet base stations, and a mobility-enhanced local-area ATM switch.
The prototype wireless network interface cards operate at peak bit-rates
up to 8 Mb/s, using low-power 2.4 GHz industrial, scientific, and
medical (ISM)-band modems. Wireless network protocols at the portable
terminal and base station interfaces support available bit rate (ABR),
variable bit rate (VBR), and constant bit rate (CBR) transport services
compatible with ATM using a dynamic time-division
multiple-access/time-division duplex (TDMA/TDD) MAC protocol for channel
sharing and data link control (DLC) protocol for error recovery. A
custom wireless control protocol is also implemented between the
portable and base units for support of radio link related functions such
as user registration and handoff. All network entities including the
portable, base and switch use a mobility-enhanced version of ATM
(“Q.2931+”) signaling for switched virtual circuit (SVC)
connection control functions, including handoff. In the first stage of
the prototype, the application-level API is TCP/UP over ATM ABR service
class using AAL5. Early experiments with the WATMnet prototype have been
conducted to validate major protocol and software aspects, including
DLC, wireless control, and mobility signaling for handoff, Selected
network-based multimedia/video applications requiring moderate bit-rates
(~0.5-1 Mb/s) in the ABR mode have been successfully demonstrated on the
laptop PC

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