Abstract: A symmetrical communication protocol allows handsets to operate as a master unit or a slave unit and operate independently of any base station. Remote units may contact each other directly with the calling unit being temporarily designated as a master unit and the called unit being designated temporarily as a slave unit. A wireless communication link is established between the two units and the units frequency-hop in synchronization in accordance with FCC requirements. The units independently monitor the signal strength of the incoming signal and can transmit power change commands to the other unit to increase or decrease transmission power as required. A calling unit initially transmits a call request on a limited number of the available frequency channels in order to decrease the acquisition time period. An idle unit has a sleep cycle and an awake cycle.

Abstract: Techniques for adapting detection schemes used in receivers for receiving radio signals are described. The received signal is processed to determine, for example, an amount of time dispersion present in the radio channel. Based on this determination an appropriate detection scheme is selected for detecting the transmitted symbols. Various techniques for determining the dispersive or non-dispersive nature of the channel are described.

Abstract: In a digital data decoder such as a Viterbi algorithm decoder, digital data transmitted over a communications channel are estimated by a receiver using a variable decision depth technique to thereby improve bit error rate (BER) and channel estimation and to reduce decision delay. In the context of conventional trellis structures used for sequence estimation, the decoder assigns group flags to each state for each time interval being considered and stores those group flags along with corresponding accumulated path metrics associated with the states. More specifically, from a just decoded state, flags from different groups, e.g. each group representing a color, number, etc., are assigned to successor states connected by a survivor path to the just decoded state. Each offspring state of a parent state is assigned the parent's group flag. The decoder detects where in the trellis all of the survivor states have the same group flag.