Power-efficient Signaling for Cellular Ofdm Systems

The design of a broadband cellular network demands powerful modulation and coding under the tight constraints of affordable modem complexity and low power consumption for the mobile terminal (MT). In order to increase battery life and allow low-cost mobile equipment to be effectively integrated in such a broadband system we propose the use of a low-rate separate signaling channel (SSC) on the physical layer. It has the primary function of power saving and takes on connectivity and mobility control functions as well as synchronization tasks. A new concept of a broadband OFDM-based FTDMA system is presented, incorporating a high rate physical data channel (D-channel) and a SSC. One application of such a concept can be a cellular ATM access network with a dynamic channel allocation wireless MAC protocol. Modem and system design issues are discussed and evaluated by simulation. A new method for calculating the output backoff (OBO) of a power amplifier for an OFDM signal is presented.