Performance bounds on bearing and symbol estimation for communication signals with side information

In this paper we develop Cramer-Rao bounds (CRBs) for bearing, symbol, and phase estimation of communications signals in flat fading channels. We do this using the constrained CRB formulation of Gorman and Hero (1999), and Stoica and Ng (1998). This provides a general framework for a large variety of cases, including semi-blind, constant modulus (CM), known cumulants, and others. These may be combined arbitrarily, e.g., we may develop CRBs for bearing estimation of constant modulus signals when a subset of the symbols are known (semi-blind, CM case). The results establish the value of side information in a large variety of communications scenarios, and may be used to compare performance of various blind and semi-blind algorithms