This paper deals with the economic tradeoffs associated with data compression in a packet switching environment.

In this paper, we first present the broadcast recognizing access method (BRAM), an access protocol suitable for regulating internode communication in either a radio or (coaxial or fiber) cable based communication system. The method avoids collisions, imposes negligible computational requirements on the nodes attempting to transmit, and is fair in the sense that no node will be indefinitely prevented from transmitting. Next we introduce parametric BRAM which attempts to balance the length of inserted channel idle periods, resulting from scheduling effects, against the probability of allowed message collisions. We show that parametric BRAM can be used to realize a method which balances inserted channel idle time against the probability of message collision to yield enhanced performance. For high message loads, parametric BRAM converges to BRAM, while for low and medium loadings it yields throughputs in excess of BRAM, and other methods. Both BRAM and parametric BRAM are discussed under the assumption of homogeneous message arrival rates at the nodes. We conclude by showing how the parametric BRAM can be applied when the nodes operate with heterogeneous or mixed message arrival rates.

The expansion in the use of land mobile communications have led to a state of congestion in that portion of the radio spectrum allocated to the land mobile service. Digital communication is one of the methods that can be applied to improve spectrum utilization. In a typical digital communication system, messages are not queued and all overlapped messages have to be retransmitted. That overlapping phenomenon has a negative impact on the performance of the system. The behavior of various determinants of system performance (like probability distribution of waiting time and the load that saturates the channel capacity) are studied in detail. A simulation model was developed to simulate four basic design approaches. It was found that a combination of randomizer (for automatic retransmission) and an inhibit signal has no significant payoff and that each one of these features is superior to a commonly used method of automatic retransmission with constant delay. The relative merits of each design is studied as a function of the load on the channel.