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https://aisel.aisnet.org/cgi/viewcontent.cgi?article=2480&context=cais

Communications of the Association for Information Systems

The present invention provides an efficient point-to-multipoint microwave ATM network including a base station (BS 205) broadcasting a continuous transmission with a sector antenna (200). The system uses time division multiplex (TDM) for downstream transmission and time division multiple access (TDMA) for upstream transmission. The downstream transmission consists of ATM cells encapsulated in MAC protocol data units (PDUs) for forward error correction (FEC) and synchronization. Small Subscriber Terminals (STs),including Subscriber Radio Units (SRUs 202), receive the broadcast and pass it to a Subscriber Access System (SAS 204) that drops the ATM cells addressed only to them. To allow strong FEC protection and to maintain the same symbol rate as the downstream transmission without sacrificing bandwidth, a modified trellis code modulation technique, which incorporates Reed Solomon coding, is used during upstream transmission.

Wireless atm metropolitan area network

This article presents a survey on medium access control protocols for multimedia traffic in wireless networks. A basic overview of MAC protocol concepts is presented, and a framework is developed on which to base qualitative comparisons. The MAC protocols covered include third-generation TDMA and CDMA schemes intended for use in a single-hop wireless system. The operation of each protocol is explained, and its advantages and disadvantages ore presented. Finally, a qualitative comparative outline of the discussed protocols is provided, based on multimedia traffic requirements.

Medium access control protocols for multimedia traffic in wireless networks

Systems and methods for tracking and managing mobile devices in a wireless network are provided. For example, the method can include discovering wireless devices connected to the wireless network, collecting association information from access points, with the association information from an access point including information identifying a current association between the access point and an associated wireless device, and providing a visualization of current associations between the access points and corresponding associated wireless devices. A conflict resolution engine may be provided for resolving conflicting access point associations.

Mobility management in wireless networks

Methods and systems for a wireless ATM network with high quality of service scheduling are provided. In one embodiment, a wireless ATM network with per-VC scheduling, a virtual framer for periodical, request-less scheduling, and a virtual shaper for request-based scheduling are provided.

Wireless atm network with high quality of service scheduling

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 (/spl sim/0.5-1 Mb/s) in the ABR mode have been successfully demonstrated on the laptop PC.

WATMnet: a prototype wireless ATM system for multimedia personal communication

A prototype microcellular wireless ATM 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 Mbps, using low-power 2.4 GHz ISM-band modems. Wireless network protocols at the portable terminal and base station interfaces support ABR, VBR and CBR transport services compatible with ATM using a dynamic 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. 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 operating at moderate bit-rates (-0.5-1 Mbps) in ABR/AALS/TCP mode have been successfully demonstrated on the laptop PC.

We provide an experimental view of radio access protocol design in wireless ATM networks. A proof-of-concept prototype, WATMnet, was developed at NEC USA C & C Research Labs, Princeton, NJ. WATMnet operates in the 2.4 GHz ISM band at a channel rate of 8 Mbps and provides an environment supporting video, audio, and data applications via a standard ATM API with both packet mode (ABR, UBR) and stream mode (CBR, VBR) services. The prototype consists of notebook computers (NEC Versa) and base stations both equipped with wireless network interface cards (WNIC). This prototype system is used to discuss the design of proposed medium access control (MAC), and data link control (DLC) protocols. Experimental results from the performance evaluation of these protocol layers, and their impact on transport layer services in the prototype system are presented.

Design and performance of radio access protocols in WATMnet, a prototype wireless ATM network

This paper presents a data link control (DLC) framework for transporting constant bit rate (CBR) traffic over wireless ATM links. The purpose of DLC in wireless is to provide error-free services to the higher layers by recovering corrupted cells. A selective reject (SREJ) automatic repeat request (ARQ) based DLC protocol is used for CBR error recovery. For an ARQ based scheme, higher recovery rates can be achieved with larger cell transfer delay, caused by cell retransmissions. Since cell transfer delay and DLC recovery rate both can translate to user-perceivable quality of service (QoS), it is important for the DLC to strike a balance between these two, depending on the application's requirements. To achieve this in our protocol, the retransmission procedure for a CBR cell is constrained to complete within a recovery time interval which is specified by the application at call-setup time. Also, a novel jitter removal algorithm, which reduces the cell delay variation caused by cell loss and retransmissions, is incorporated as a part of the DLC protocol. The proposed protocol is implemented on NEC's WATMnet prototype system. The implementation and its experimental results are reported for illustrating the performance and feasibility of the presented CBR DLC protocol. The experimental results show that the DLC protocol can be successfully applied for error recovery of CBR traffic on a per-connection basis. These also indicate that the DLC can be programmed to attain a desirable tradeoff between cell transfer delay and cell recovery rate.

Design and implementation of data-link control protocol for CBR traffic in wireless ATM networks

Wireless ATM provides a framework for next-generation wireless communication networks supporting integrated, quality-of-service (QoS) based multimedia services. The reference architecture for wireless ATM consists of two major components-a radio access layer for extension of ATM services over a wireless link, and a mobile ATM infrastructure network capable of supporting terminal mobility. We discuss the design considerations and implementation issues for the radio access layer protocols (for example, medium access control (MAC), data link control (DLC), etc.) in wireless ATM networks. A brief overview of recent experiences (implementation and experimental evaluation) with WATMnet, a proof-of-concept prototype of a Wireless ATM network developed at NEC USA's C&C Research Labs in Princeton, NJ, is also presented.

P. Narasimhan

Papers

WATMnet: a prototype wireless ATM system for multimedia personal communication

WATMnet: a prototype wireless ATM system for multimedia personal communication

Design and performance of radio access protocols in WATMnet, a prototype wireless ATM network

Design and implementation of data-link control protocol for CBR traffic in wireless ATM networks

Design and implementation of radio access protocols in wireless ATM networks