Ahstrucf-A model is proposed for the situation where M users share a common communication resource but, because of unknown time offsets among their clocks, cannot transmit their data packets in a time-sharing mode and, because of the lack of a feedback link, can never determine these time offsets and also can never be sure of the outcomes of their individual packet transmissions. Each user is r...

Transmit diversity in the presence of channel feedback at the transmitter is analyzed in this paper. We first consider perfect channel feedback and summarize the beamforming solution which minimizes the codeword error probability. We note that the error probability minimizing scheme is different from the mutual information maximizing scheme. We then present a scheme with partial channel feedbac...

We report on the fabrication and characterization of a distributed feedback channel waveguide laser in erbium-doped aluminium oxide on a standard thermally oxidized silicon substrate. Holographically-written surface-relief Bragg gratings have been integrated with the aluminium oxide waveguides via reactive ion etching of a silicon dioxide overlay film. The laser operates at a wavelength of 1545...

In a high-speed moving mobile environment, the channel state information (CSI) in last part of packet is different from actual beginning part. Therefore, estimation accuracy degraded, especially when small number pilot symbols are used to ensure transmission efficiency. For above reasons, it necessary compensate for CSIs achieve reliable communication. Decision feedback (DFCE) has been widely c...

This paper proposes a novel scalable approach to reduce the feedback for downlink multiuser diversity in multiple input multiple output (MIMO) systems. We propose a feedback protocol that features a contention channel consisting of a fixed number of feedback minislot to convey channel state information. Feedback control parameters such as channel quality threshold and feedback probability are j...

The energy-optimal scheme is found for communicating one bit over a memoryless Gaussian channel with an ideal feedback channel. It is assumed that the channel is allowed to be used at most N times before decoding. The optimal coding/decoding strategy is derived by dynamic programming. It is found that feedback gives a significant performance gain and that the optimal strategies are discontinuou...

A bandwidth-efficient variable-rate adaptive channel coding scheme, ATCQAM, for time-varying flat-fading channels is proposed. In addition to the forward channel, a low-capacity feedback channel is needed to convey channel state information to the transmitter, possibly with delays and noise. A number of transmission modes, with varying throughputs, are incorporated at the transmitter. Appropria...

Because of the large numbers of feedback in the multiple input & multiple output (MIMO) multi-carrier system, the precoding based on full channel state information is difficult to be applied in practical. In order to significantly reduce the overhead of the feedback link, a compressed sensing precoding method with limited feedback in MIMO multi-carrier system is proposed in this paper. First, t...

Multiple access channel with feedback is an extension of classical MAC, by providing senders with ability to observe the channel output. The capacity region in the general case is not known. This report presents the main results of [1] by Cover and Leung, which is a region of achievable rates exceeding the capacity region of classical MAC (section 3). Since the coding technique used in [1] reli...