EFFICIENT MULTIPLEXING OF INTERMITTENT TRANSMITTERS
Abstract
The limit of channel utilization is studied by postulating a model of a band-limited, noisy channel that incorporates the feature of random selection of a subset of transmitters to be multiplexed within the bandwidth. It is shown by a random coding argument that sets of waveforms certainly exist that can provide operation without interference for any finite number of transmitters assigned to the channel, provided only that the total information transmitted by any subset of transmitters be appropriate for the signal powers involved. This requirement is much weaker than the usual restriction that the waveforms assigned to different transmitters be orthogonal; under conditions of fractional utilization it permits operating at greater rates, or in smaller bandwidths. The effect of coding restrictions is to increase the power requirement. The required increase in power is not excessive, however. Even at the minimum length represented by binary coding, an example using waveforms taken from a systematically related set shows that a power increase of 7 db permits ten transmitters to be assigned to a bandwidth appropriate for three, if not more than three are active simultaneously. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1961
- Accession Number
- AD0262544
Entities
People
- F.f. Jr. Fulton
Organizations
- Lockheed Martin Missiles and Space