Equilibrium point analysis is used to evaluate system behavior in a packet reservation multiple access (PRMA) protocol based network. The authors derive the probability of packet dropping given the number of simultaneous conversations. The authors establish conditions for system stability and efficiency. Numerical calculations based on the theory show close agreement with computer simulations. They also provide valuable guides to system design. Because PRMA is a statistical multiplexer, the channel becomes congested when too many terminals are active. For a particular example it is shown that speech activity detection permits 37 speech terminals to share a PRMA channel with 20 slots per frame, with a packet dropping probability of less than 1%. >

Performance of PRMA: a packet voice protocol for cellular systems

A network for providing sensing, communications and control. In the present invention a plurality of intelligent cells (27, 28), each comprising an integrated circuit having a processor and input/output sections are coupled in a network. Each of the programmable cells includes a unique identification number (ID) at the time it is manufactured. When organized in a network, each of the cells performs at least one of the following functions: (1) sensing, (2) communicating, (3) controlling. Groups of cells may be organized to perform group functions and may be assigned a group ID. Cells and groups may be referenced by cell ID and group ID.

Network and intelligent cell for providing sensing bidirectional communications and control

Packet-reservation multiple access (PRMA) is viewed as a merger of slotted ALOHA and time-division multiple access (TDMA). Dispersed terminals transmit packets of speech information to a central base station. When its speech activity detector indicates the beginning of a talkspurt, a terminal contends with other terminals for access to an available time slot. After the base station detects the first packet in the talkspurt, the terminal reserves future time slots for transmission of subsequent speech packets. The influence of several variables on PRMA efficiency, defined as the number of conversations per channel, is examined. The number of channels is the ratio of transmission rate to speech coding rate. It is found that with 32-kb/s speech coding and 720-kb/s transmission (22.5 channels), PRMA supports up to 37 simultaneous conversations, or 1.64 conservations per channel. The number of conversations per channel is at least 1.5 over a wide range of packet sizes (8 ms of speech per packet to 34 ms) and for all systems with 16 or more channels (transmission rate >or=512 kb/s, with 32-kb/s speech coding). Other factors studied are the sensitivity of the speech activity detector, the retransmission probability of the contention scheme, and the maximum time delay for the transmission of speech packets. >

Efficiency of packet reservation multiple access

The future of third-generation wireless networking is discussed. The vision of the third generation is a single set of standards that can meet a wide range of wireless access applications. Third-generation systems, in harmony with broadband integrated services digital networks, will use shared resources to convey many information types. A single network architecture will serve its users efficiently in many environments, including moving vehicles, indoor and outdoor public areas, residences, offices, and factories. A study of a switching architecture, referred to as a cellular packet switch, and a packet transmission technique, referred to as a packet reservation multiple access is discussed. By means of a design example, it is shown how these techniques can work together to meet some of the demands of third-generation systems. >

Cellular packet communications

The evolution of wireless information networks is traced from the present first generation systems to next century's third generation. The third generation is envisioned as a unified wireless access replacing the diverse and incompatible second-generation networks with a single means of wireless access to advanced information services. Four issues are examined: the goal a network is designed to achieve, network architecture, radio transmission technology, and the control channels that make it possible for wireless terminals and the remainder of the network to coordinate their operations. In the framework of these issues, present networks are described; the properties of four second-generation networks, GSM, IS-54, CT2, and DECT, are cited; and early work in progress at the Rutgers WINLAB is described. The latter is a packet-reservation multiple-access scheme that can be viewed as a combination of TDMA and slotted ALOHA. >

Trends in cellular and cordless communications

In packet broadcast networks, users are interconnected via a broadcast channel. The key problem is multiple access of the shared broadcast channel. The performance of the R-ALOHA protocol for multiple access is studied in this paper. Two user models with Poisson message arrivals are analyzed; each message consists of a group of packets with a general probability distribution for group size. In the first model, each user handles one message at a time. In the second model, each user has infinite buffering capacity for queueing. Analytic models are developed for characterizing message delay and channel utilization. Bounds on channel throughput are established for two slightly different protocols. Numerical results from both analysis and simulation are presented to illustrate the accuracy of the analytic models as well as performance characteristics of the R-ALOHA protocol.

Packet Broadcast Networks&#8212;A Performance Analysis of the R-ALOHA Protocol

The convolution algorithm, the mean value analysis (MVA) algorithm, and the LBANC algorithm are major algorithms for the solution of closed product-form queueing networks. For fixed-rate service centers, the efficiency of each algorithm is greatly improved by a recursive solution. We show that the recursive relations in all three algorithms are closely related so that each one can be easily derived from any of the others.

A Simple Derivation of the MVA and LBANC Algorithms from the Convolution Algorithm

An experimental study was conducted using a network simulator to investigate the performance of packet communication networks as a function of: the network resource capacities (channels, buffers), the network load (number of virtual channels, virtual channel loads), protocols (flow control, congestion control, routing), and protocol parameters (virtual channel window size, input buffer limits). Performance characteristics are shown and the design of input buffer limits for network congestion control, virtual channel window size, and nodal buffer capacity addressed. Network design strategies for the control of load fluctuations are proposed and discussed.

Lam

Papers

Packet Broadcast Networks—A Performance Analysis of the R-ALOHA Protocol

A Simple Derivation of the MVA and LBANC Algorithms from the Convolution Algorithm

Congestion Control of Packet Communication Networks by Input Buffer Limits—A Simulation Study

Lam

Papers

Packet Broadcast Networks&#8212;A Performance Analysis of the R-ALOHA Protocol

A Simple Derivation of the MVA and LBANC Algorithms from the Convolution Algorithm

Congestion Control of Packet Communication Networks by Input Buffer Limits&#8212;A Simulation Study

Packet Broadcast Networks—A Performance Analysis of the R-ALOHA Protocol

Congestion Control of Packet Communication Networks by Input Buffer Limits—A Simulation Study