Topic
Communication channel
About: Communication channel is a research topic. Over the lifetime, 137411 publications have been published within this topic receiving 1715077 citations. The topic is also known as: communication channel & communications channel.
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TL;DR: In this paper, an accurate and convenient method to determine an effective MOSFET channel length is proposed based on a computer aided evaluation of an intrinsic channel resistance without using special test devices.
Abstract: An accurate and convenient method to determine an effective MOSFET channel length is proposed. This method is based on a computer aided evaluation of an intrinsic MOSFET channel resistance without using special test devices. N-channel silicon-gate MOSFETs were fabricated, and the channel length and its range of device to device scatter were evaluated . To define an effective channel, a simple model of the source-drain (S-D) diffusion layer is proposed. This model shows that the expected transition layer resistance between the S-D diffusion layer and the inverted channel layer agrees with the experimental results. The accuracy of this method is also discussed. It is found to be better than 0.1 µm.
269 citations
TL;DR: Several techniques for improving the bounds are developed: (1) causally conditioned entropy and directed information simplify the inner bounds, (2) code trellises serve as simple code trees, (3) superposition coding and binning with code trees improves rates.
Abstract: A discrete memoryless network (DMN) is a memoryless multiterminal channel with discrete inputs and outputs. A sequence of inner bounds to the DMN capacity region is derived by using code trees. Capacity expressions are given for three classes of DMNs: (1) a single-letter expression for a class with a common output, (2) a two-letter expression for a binary-symmetric broadcast channel (BC) with partial feedback, and (3) a finite-letter expression for push-to-talk DMNs. The first result is a consequence of a new capacity outer bound for common output DMNs. The third result demonstrates that the common practice of using a time-sharing random variable does not include all time-sharing possibilities, namely, time sharing of channels. Several techniques for improving the bounds are developed: (1) causally conditioned entropy and directed information simplify the inner bounds, (2) code trellises serve as simple code trees, (3) superposition coding and binning with code trees improves rates. Numerical computations show that the last technique enlarges the best known rate regions for a multiple-access channel (MAC) and a BC, both with feedback. In addition to the rate bounds, a sequence of inner bounds to the DMN reliability function is derived. A numerical example for a two-way channel illustrates the behavior of the error exponents.
269 citations
TL;DR: It is demonstrated that quality improvement can be realized when a new channel is introduced in dual-channel supply chains, and the effects of the quality sensitivity parameters of different channels on price and product quality, as well as profits and consumer surplus are shown.
268 citations
16 Nov 2003
TL;DR: In this paper, the authors presented UWB channel measurements from 3 to 6 GHz for a body area network (BAN) in an anechoic chamber and an office room.
Abstract: The paper presents UWB channel measurements from 3 to 6 GHz for a body area network (BAN) in an anechoic chamber and an office room. Both, transmit and receive antenna were placed directly on the body. Channel parameters as delay spread and path loss are extracted from the measurements and the influence of the body is highlighted. We show that in some situations there are significant echoes from the body (e.g. from the arms) and we observed deterministic echoes from the floor that could help to simplify a RAKE receiver structure. Finally, we consider the overall energy consumption of the BAN and give decision regions for singlehop and multihop links in relation to signal processing energy.
268 citations
TL;DR: This paper proposes multimode antenna selection, which uses a low-rate feedback channel to improve the error rate performance of spatial multiplexing systems with linear receivers.
Abstract: Spatial multiplexing is a simple transmission technique for multiple-input multiple-output (MIMO) wireless communication links in which data is multiplexed across the transmit antennas. In Rayleigh fading matrix channels, however, spatial multiplexing with low-complexity linear receivers suffers due to a lack of diversity advantage. This paper proposes multimode antenna selection, which uses a low-rate feedback channel to improve the error rate performance of spatial multiplexing systems with linear receivers. In the proposed technique, both the number of substreams and the mapping of substreams to antennas are dynamically adjusted, for a fixed total data rate, to the channel based on limited feedback from the receiver. Dual-mode selection, where spatial multiplexing or selection diversity is adaptively chosen, dramatically improves the diversity gain achieved. Multimode selection (i.e., allowing any number of substreams to be dynamically selected) provides additional array gain. Various criteria for selecting the number of substreams and the optimal mapping of substreams to transmit antennas are derived. Relationships are made between the selection criteria and the eigenmodes of the channel. A probabilistic analysis of the selection criteria are provided for Rayleigh fading channels. Applications to nonlinear receivers are mentioned. Monte Carlo simulations demonstrate significant performance improvements in independent and identically distributed (i.i.d.) flat-fading Rayleigh matrix channels with minimal feedback.
268 citations