Minimizing Channel Density with Movable Terminals

We give algorithms to minimize density for VLSI channel routing problems with terminals that are movable subject to certain constraints. The main cases considered are channels with linear order constraints, channels with linear order constraints and separation constraints, channels with movable modules containing fixed terminals, and channels with movable modules and terminals. In each case, we improve previous results for running time and space by a factor of L/\lgn and L, respectively, where L is the channel length, and n is the number of terminals

Packetized-voice/data integrated transmission on a token passing ring local area network

This paper investigates the performance of a token passing ring network with packetized-voice/data mixed traffic through extensive simulations. Both data and voice users are modeled in the simulations. Data users produce bursty traffic. Voice traffic is modeled as having alternating talkspurts and silences, with generation of voice packets at a constant rate during talkspurts and no packet generation during silence periods.The network performance measures obtained include: the distribution of transmission delays for voice packets, the average transmission delay and loss probabilities for voice packets, the number of voice users allowed on a network while satisfying the real-time constraints of speech, and the average transmission delay for data packets.Token passing ring local area networks are shown to effectively handle both voice and data traffic. The effects of system parameters (e.g., voice packet length, talkspurt/silence lengths, data traffic intensity, and limited versus exhaustive service disciplines) on network performance are discussed

Traffic Optimization for Multimodal Cooperative Networks

Resource allocation and traffic optimization are crucial problems in multi-traffic wireless networks as resources are scarce and the traffic is shared by multiple users. When application performance is the key concern in a network, utility is considered as a reliable metric. A lot of research has been done on capacity limits of wireless networks under some assumptions on the physics of propagation and some restrictions on the communication strategy employed by the nodes. It has been proved that due to the physical limitation that holds for any communication system, the decrease in throughput problem as wireless nodes increase in a fixed area cannot be overcome. In this thesis, multimodal networks, where other modes of communication like wires, infrared links may operate in addition to wireless nodes to improve the performance of the wireless network are studied and rate and power optimization problems are considered.;In this thesis, rate and power optimizations for heterogeneous traffic multimodal networks are proposed by solving them separately. First, the total rate is divided between delay-sensitive data and voice to achieve maximum utility in the network and in the next step, we divide transmit power between the wireless channel and the wired channel for a source-destination pair multimodal network and a diamond cooperative multimodal network implemented with Lanemann protocol. We consider a utility function for delay-sensitive data as a function of rate, reliability and delay and, the utility function of voice is a function of rate and delay. Traffic optimization problem is then solved by maximizing the sum of utilities of all voice and data users in the network and optimal rates that can be allocated to data and voice are calculated. Power allocation for a source-destination pair multimodal networks is done by optimizing instantaneous rate and outage probability in the network. For implementing a cooperative wireless relay network, we consider two cases: wire place between source and relay and wire placed between relay and destination. Optimal power allocation to wired and wireless channels is done by analytically minimizing the high-SNR outage probability expressions

On-board processing for future satellite communications systems: Satellite-Routed FDMA

A frequency division multiple access (FDMA) 30/20 GHz satellite communications architecture without on-board baseband processing is investigated. Conceptual system designs are suggested for domestic traffic models totaling 4 Gb/s of customer premises service (CPS) traffic and 6 Gb/s of trunking traffic. Emphasis is given to the CPS portion of the system which includes thousands of earth terminals with digital traffic ranging from a single 64 kb/s voice channel to hundreds of channels of voice, data, and video with an aggregate data rate of 33 Mb/s. A unique regional design concept that effectively smooths the non-uniform traffic distribution and greatly simplifies the satellite design is employed. The satellite antenna system forms thirty-two 0.33 deg beam on both the uplinks and the downlinks in one design. In another design matched to a traffic model with more dispersed users, there are twenty-four 0.33 deg beams and twenty-one 0.7 deg beams. Detailed system design techniques show that a single satellite producing approximately 5 kW of dc power is capable of handling at least 75% of the postulated traffic. A detailed cost model of the ground segment and estimated system costs based on current information from manufacturers are presented

Application of advanced on-board processing concepts to future satellite communications systems: Bibliography

Abstracts are presented of a literature survey of reports concerning the application of signal processing concepts. Approximately 300 references are included

On the design and implementation of a wafer yield editor

An interactive environment is presented for the analysis of yield information required on modern integrated circuit manufacturing lines. The system estimates wafer yields and wafer-yield variations, quantifies regional yield variations within wafers, identifies clusters in wafers and/or in lots, and is able to predict wafer yields via simple simulation tools. An analysis approach based on site yields makes the system independent of the product and of the technology. The analysis technique makes it possible to investigate the effects of both correlated and uncorrelated sources of yield loss. The statistical information obtained can be used to study changes in the technological process. Graphical displays in the form of wafer maps are used to represent the spatial distribution of dice in the wafer. Capabilities for such as radial and angular distribution analyses, among others, are provided to examine data, and hypothetical wafer maps are created to visualize and predict simulated wafer yield

Multilink and AUV-Assisted Energy-Efficient Underwater Emergency Communications

Recent development in wireless communications has provided many reliable solutions to emergency response issues, especially in scenarios with dysfunctional or congested base stations. Prior studies on underwater emergency communications, however, remain under-studied, which poses a need for combining the merits of different underwater communication links (UCLs) and the manipulability of unmanned vehicles. To realize energy-efficient underwater emergency communications, we develop a novel underwater emergency communication network (UECN) assisted by multiple links, including underwater light, acoustic, and radio frequency links, and autonomous underwater vehicles (AUVs) for collecting and transmitting underwater emergency data. First, we determine the optimal emergency response mode for an underwater sensor node (USN) using greedy search and reinforcement learning (RL), so that isolated USNs (I-USNs) can be identified. Second, according to the distribution of I-USNs, we dispatch AUVs to assist I-USNs in data transmission, i.e., jointly optimizing the locations and controls of AUVs to minimize the time for data collection and underwater movement. Finally, an adaptive clustering-based multi-objective evolutionary algorithm is proposed to jointly optimize the number of AUVs and the transmit power of I-USNs, subject to a given set of constraints on transmit power, signal-to-interference-plus-noise ratios (SINRs), outage probabilities, and energy, which achieves the best tradeoff between the maximum emergency response time (ERT) and the total energy consumption (EC). Simulation results indicate that our proposed approach outperforms benchmark schemes in terms of energy efficiency (EE), contributing to underwater emergency communications.Comment: 15 page

A complete design path for the layout of flexible macros

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