Random time and frequency hopping for unslotted asynchronous access

Two kinds of interleaved codes are considered for unslotted asynchronous multiple access collision channel without feedback, for random time hopping, and also through L such parallel channels for random frequency hopping. Exponential upper bounds are given on the decoding error probability. Each of these bounds consists of a first term due to overflow and a second term due to collision under no overflow. For both kinds of interleavings essentially the same throughput limiting role of the channel capacity is exhibited as known for slotted access with a single code. For one of the rules the same error probability limit is guaranteed at the same throughput both for the unslotted and for the slotted case