Distributed Scheduling Conflict-Free Multiple Access for Local Area Communication Networks

A conflict-free distributed scheduling multiple access (DSMA) scheme using a high-speed main channel for data transmission and a subchannel for distributed decision scheduling is described and analyzed. DSMA, which has a variable cycle length and employs a slow speed subchannel for scheduling, is suitable for local area communication networks which employ a data bus as transmission support. With the data rate of the main channel and subchannel represented, respectively, by r
p
and r
q
, the maximum channel occupancy is given by
C_{max} = r_{p}/(r_{p} + r_{q})
. Numerical results show that DSMA is very efficient and exhibits a delay-throughput characteristic close to that of the
M/D/1
perfect scheduling lower bound over a wide range of throughput values. DSMA guarantees each active user one slot per cycle. In addition, DSMA permits priority scheduling.