Dedicated versus Half-Duplex Receiver Topology in Jammed, Fully Connected CDMA Networks: Theory and Numerical Comparisons

摘要

In our previous report we introduced the notion of topology-selective jamming in conjunction with a fully-connected network topology, equipped with CDMA capability. Spread-spectrum modulation was employed, both as a multiple-access tool as well as an antijam aid. In particular, we assumed an arbitrary topology of dedicated transmitters (TR) and receivers (RVCR) in a statistically symmetrical model, where every TR can be heard by every RCVR; in this sense, the network is fully-connected. The number of TRs (NT) was fixed and, in general, different from the number of RCVRs, NR. A special case is when NT=NR, which is essentially equivalent to a network of full duplex modems. Since full-duplex is but a special case, we prefer the nomenclature 'dedicated', which is applicable to more general scenarios such as multi-receiver satellites, two-level hierarchical networks with dedicated receivers/repeaters, etc. In such environments, the present theory would provide performance estimates (throughput-delay) within a 'local' subnet of connected radios. The goal of the present report is to extend that theory to the case where the modems are nondedicated, i.e., half-duplex. This means that a unit will alternate between the receiving mode and the transmitting mode; it is not dedicated solely to either of the two functions and it cannot do both at the same time, as in the full-duplex case. (RH)