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In this paper, we analyze the performance of a dual- hop system with partial relay selection and feedback delay over Rayleigh fading channels in the presence of multiple identical interferers at the destination. Based on the new closed-form expressions for the cumulative distribution function of the effective signal-to-interference plus noise ratio, we present closed-form expressions for the outage...
This paper presents the results of frequency domain channel sounding of wireless in-car channels. Based on an extended measurement campaign different application-specific channels are characterized by channel gain, cumulative density functions and time dispersion parameters. The measurement sets are chosen for the freely disposable industrial, scientific and medical (ISM) frequency bands. Characteristic...
Traditional scheduling algorithms are focused in maximizing system throughput considering a grade of fairness. However, maximizing the system throughput does not necessarily result in maximizing the number of satisfied users (users with a packet delay below a threshold). More over, the throughput maximization could cause a low grade of fairness. In this paper, we propose a low complexity scheduling...
Ultra wideband (UWB) communication was evaluated within a closed space, with a view to partly replacing onboard data buses with wireless connections. Spatial distributions of UWB propagation in frequency (from 3.1 to 10.6 GHz), time domains and throughput with use of a radio absorber were derived from measured. It was also found that delay spreads can be suppressed by partially panelling a radio absorber...
This paper presents an Equivalent-Figure-of-Merit (EFOM) for designing and evaluating a wireless system towards low power and high performance. Relevant factors like delay, minimum latency, overhead length of a package, package length, data rate, bit-error-rate (BER), pre-receiving time of the receiver, average duty cycle and electronics performance factor are synthesized within a unique model. Comparing...
This paper presents the results of an empirical study of wireless propagation channels for vehicle-to-vehicle communications in street intersections, a scenario especially important for collision avoidance applications. The results are derived from a channel measurement campaign performed at 5.6 GHz in four different types of urban intersections. We present results on typical power delay profiles,...
It has been reported that channel attenuation and Root-Mean-Square Delay Spread (RMS-DS) of in-home (IH) power line (PL) channels are (positively) correlated lognormal random variables. Exploiting this result, we here propose a simple statistical channel model where tap amplitudes and differential delay are correlated random variables. Although we focus here on the IH PL channel, we also report empirical...
Ultra wideband (UWB) propagation was measured and characterized within spacecrafts, with a view to partly replacing onboard data buses with wireless connections. Spatial distributions of UWB and narrowband propagation in frequency (from 3.1 to 10.6 GHz) and time domains were measured with a microwave vector network analyzer. While narrowband resulted in a number of dead spots (deep fading points)...
In this paper we investigate the 60 GHz in-car wideband radio channel to assess the feasibility of 60 GHz high bit rate radio communication inside a car. The investigations are based on a measurement campaign comprising different application-oriented transmission scenarios and propagation conditions. We analyze the channel gain, time dispersion and frequency selectivity. Finally, we derive the achievable...
In this paper, we study the power allocation scheme for a single user, multi-channel system, e.g. orthogonal frequency- division multiplexing (OFDM) systems, under time-variant wireless fading channels. We assume the receiver feeds back perfectly estimated channel state information (CSI) to the transmitter after a processing delay. The objective of the power allocation is to maximize physical (PHY)...
The work thus presents GEWE-RC MOSFET as a potential candidate for high performance RF applications and achieves fi of 48.6 GHz which is a 31.7 % and 48.5 % improvement as compared to the RC and bulk respectively, at Vgs = 1.0 V, for same set of design parameters, owing to the improved gate controllability and reduced parasitic capacitances. Moreover,intrinsic delay and high gains pertained by GEWE-RC...
This paper deals with a simple but essential two-hop wireless relay network employing network coding and a slotted ALOHA protocol. Network coding is a recent and highly regarded technology for capacity enhancement on multiple unicast and multisource multicast networks. However, the performance of network coding on wireless relay networks employing random access protocols has not been analyzed. This...
In this paper, we consider the multicast channel in a cellular network wherein all the users within a cell request a common information stream from the base station. In addition to data streaming this can also model control channels in the cell as opposed to the regular data channels used for user specific information transmission. While the multicast transmission in a single cell environment has...
Seamless vertical handover is one of the major challenges toward seamless inter-networking between heterogeneous access networks. To perform seamless vertical handover even under bad radio conditions in network mobility (NEMO) environments, NEMO-SHO has been proposed as an IPv6 soft handover extension that allows packet bicasting via two different wireless links simultaneously. However, the performance...
In this paper, we study the implication of wireless broadcast for data aggregation in lossy wireless sensor networks. Each sensor node generates information by sensing its physical environment and transmits the information to a special node called the sink, via multi-hop communications. The goal of the network system is to compute a function at the sink from the information gathered by spatially distributed...
In many DSP applications (image and voice processing, baseband symbol decoding in high quality communication channels) several dBs of SNR loss can be tolerated without noticeable impact on system level performance. For power optimization in such applications, voltage overscaling can be used to operate the arithmetic circuitry slower than the critical circuit path delay while incurring tolerable SNR...
The concept of effective capacity offers a novel methodology to investigate the impact that design decisions at the physical layer may have on system performance at the link layer. Assuming a constant flow of incoming data, the effective capacity characterizes the maximum arrival rate that a wireless system can support as a function of its service requirements. Service requirements in this framework...
In this paper, an energy efficient adaptive modulation scheme is proposed for a wireless cognitive radio ad hoc network, where each node is equipped with cognitive radio and the network is an OFDMA system operating on time slots. In each slot, the users with new traffic demand will sense the spectrum and locate the available subcarrier set. Then they choose subcarriers with favorable channel condition...
A delay-locked loop of multi-band selector with wide-locking range and low power dissipation is presented. The architecture of the proposed delay-locked loop consists of phase frequency detector, charge pump, band selector, multi-control delay line, and start-up circuit. The multi-band selector is used to extend operation frequency of delay-locked loop by switching the multi-control delay line. The...
We consider the problem of exchanging packets from the individual queues at multiple wireless terminals with the assistance of a single relay node. In an earlier paper, we studied this for a backlogged traffic model, where each node always had packets to transmit. Here, we consider stochastically varying packet traffic and compare the stable operation under plain routing, and digital and analog network...
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