This paper examines different designs for combined channel estimation and decoding for a point to point time varying frequency selective fading channel. The channel state information (CSI) is not known a priori at either the transmitter or the receiver. Channel estimation is performed through a combination of conventional pilots and manufactured pilots from previously decoded data. The paper examines how different interleaver structures affect the tradeoff between achievable rates, delay and complexity. When there is no delay constraint at all, the conventional pilots can be eliminated completely and a proper interleaving scheme can convert half the symbols into manufactured pilots. When there is a delay constraint, the paper explores various interleaver structures that combine the conventional pilots with the manufactured pilots in different ways to get much better achievable rates than conventional pilot-symbol aided channel estimation.

This paper presents analytical upper and lower bounds on the information rate of a multiuser Rayleigh fading channel with no channel state information (CSI) at the transmitters or the receivers. These bounds are shown to converge whenever an individual user's data rate is small compared with the bandwidth, e.g., when users can employ CDMA. The amount of spreading required for a given degree of convergence depends on the number of receive antennas. The number of users can be sufficient for the aggregate spectral density to be large. The paper presents exact analytical expressions for the information rates of both the block fading and the continuous correlated fading channel models in this regime. Finally, the results are extended to more general channel models.

This paper studies the performance of bit interleaved coded modulation (BICM) with a single decision feedback. The separation of demodulation and decoding in BICM inevitably reduces the channel's capacity. Altering the conventional bit mapping in BICM and allowing a single decision feedback greatly reduces the capacity loss. The extra complexity introduced by the single decision feedback appears well justified for dense constellations.

This talk presents analytical upper and lower bounds on the information rate of a multiuser Rayleigh fading channel with no channel state information (CSI) at the transmitters or the receivers. These bounds are shown to converge whenever an individual userpsilas data rate is small compared with the bandwidth, e.g., when users can employ CDMA. The amount of spreading required for a given degree of convergence depends on the number of receive antennas; however, the number of users can be sufficient for the aggregate spectral density to be large. The talk presents exact analytical expressions for the information rates of both the block fading and the continuous correlated fading channel models in this regime and presents techniques for extending these to more general channel models.

This paper first presents an optimal receiver and coding scheme for a multi-user, multi-receiver, non-coherent Rayleigh flat fading channel which achieves the channel's constrained capacity (i.e., the capacity for a fixed input distribution). The paper then goes on to analyze the optimal receiver and uses it to generate tight upper and lower bounds on the constrained capacity. Knowing this constrained capacity is essential to judge the efficiency of coding schemes for the channel; it performs the same function as BPSK capacity for the AWGN channel in judging LDPC codes. The paper then goes on to present a practicable correlation based receiver that uses a novel iterative channel estimation technique. The performance of this receiver remains close to the constrained capacity as long as the per-user SNR is low; there is no requirement on the aggregate SNR. With 50 users, 50 receivers and a brickwall fading channel with a coherence length of 200 symbols, for example, the correlation based receiver achieves a sum rate of 36 bits/sec/Hz, significantly greater than any current cellular standards.

This work studies the performance of Bit Interleaved Coded Modulation with a single decision feedback. The separation of demodulation and decoding in BICM inevitably reduces the channelpsilas capacity. Altering the conventional bit-mapping in BICM and allowing a single decision feedback greatly reduces the capacity loss. The extra complexity due to the single decision feedback appears well justified for dense constellations.