An experimental VLSI implementation of low-overhead symbol timing and frequency offset estimation for TDMA portable radio applications

The author describes the algorithms and the low-complexity implementation structures used in an experimental prototype VLSI circuit to perform low-overhead symbol timing and frequency offset estimation for reception of TDMA (time-division multiple-access) bursts in a portable radio environment. Short TDMA bursts with a minimum of overhead are desirable to achieve efficient communication with low delay. Using application-specific digital signal processing, QPSK (quadrature phase-shift keying) modulation is efficiently demodulated using block processing techniques. Only one analog-to-digital converter is required with only 4 b of resolution to sample a low-frequency intermediate-frequency bandpass signal for digital processing. A silicon compiler implementation of burst symbol timing with optimization of processing circuits resulted in a moderately sized chip using 1.2-μm design rules