3,889 research outputs found
A low-cost time-hopping impulse radio system for high data rate transmission
We present an efficient, low-cost implementation of time-hopping impulse
radio that fulfills the spectral mask mandated by the FCC and is suitable for
high-data-rate, short-range communications. Key features are: (i) all-baseband
implementation that obviates the need for passband components, (ii) symbol-rate
(not chip rate) sampling, A/D conversion, and digital signal processing, (iii)
fast acquisition due to novel search algorithms, (iv) spectral shaping that can
be adapted to accommodate different spectrum regulations and interference
environments. Computer simulations show that this system can provide 110Mbit/s
at 7-10m distance, as well as higher data rates at shorter distances under FCC
emissions limits. Due to the spreading concept of time-hopping impulse radio,
the system can sustain multiple simultaneous users, and can suppress narrowband
interference effectively.Comment: To appear in EURASIP Journal on Applied Signal Processing (Special
Issue on UWB - State of the Art
Pulse interspersing in static multipath chip environments for Impulse Radio communications
Communications are becoming the bottleneck in the performance of Chip Multiprocessor (CMP). To address this issue, the use of wireless communications within a chip has been proposed, since they offer a low latency among nodes and high reconfigurability. The chip scenario has the particularity that is static, and the multipath can be known a priori. Within this context, we propose in this paper a simple yet very efficient modulation technique, based on Impulse Radio-On–Off-Keying (IR-OOK), which significantly optimizes the performance in Wireless Network-on-Chip (WNoC) as well as off-chip scenarios. This technique is based on interspersing information pulses among the reflected pulses in order to reduce the time between pulses, thus increasing the data rate. We prove that the final data rate can be considerably increased without increasing the hardware complexity of the transceiver.Peer ReviewedPostprint (published version
Energy-Efficient Power Control in Impulse Radio UWB Wireless Networks
In this paper, a game-theoretic model for studying power control for wireless
data networks in frequency-selective multipath environments is analyzed. The
uplink of an impulse-radio ultrawideband system is considered. The effects of
self-interference and multiple-access interference on the performance of
generic Rake receivers are investigated for synchronous systems. Focusing on
energy efficiency, a noncooperative game is proposed in which users in the
network are allowed to choose their transmit powers to maximize their own
utilities, and the Nash equilibrium for the proposed game is derived. It is
shown that, due to the frequency selective multipath, the noncooperative
solution is achieved at different signal-to-interference-plus-noise ratios,
depending on the channel realization and the type of Rake receiver employed. A
large-system analysis is performed to derive explicit expressions for the
achieved utilities. The Pareto-optimal (cooperative) solution is also discussed
and compared with the noncooperative approach.Comment: Submitted to the IEEE Journal on Selected Topics in Signal Processing
- Special issue on Performance Limits of Ultra-Wideband System
Wideband performance comparison between the 40 GHz and 60 GHz frequency bands for indoor radio channels
When 5G networks are to be deployed, the usability of millimeter-wave frequency allocations seems to be left out of the debate. However, there is an open question regarding the advantages and disadvantages of the main candidates for this allocation: The use of the licensed spectrum near 40 GHz or the unlicensed band at 60 GHz. Both bands may be adequate for high performance radio communication systems, and this paper provides insight into such alternatives. A large measurement campaign supplied enough data to analyze and to evaluate the network performance for both frequency bands in different types of indoor environments: Both large rooms and narrow corridors, and both line of sight and obstructed line of sight conditions. As a result of such a campaign and after a deep analysis in terms of wideband parameters, the radio channel usability is analyzed with numerical data regarding its performance
A Genetic Algorithm Based Finger Selection Scheme for UWB MMSE Rake Receivers
Due to a large number of multipath components in a typical ultra wideband
(UWB) system, selective Rake (SRake) receivers, which combine energy from a
subset of multipath components, are commonly employed. In order to optimize
system performance, an optimal selection of multipath components to be employed
at fingers of an SRake receiver needs to be considered. In this paper, this
finger selection problem is investigated for a minimum mean square error (MMSE)
UWB SRake receiver. Since the optimal solution is NP hard, a genetic algorithm
(GA) based iterative scheme is proposed, which can achieve near-optimal
performance after a reasonable number of iterations. Simulation results are
presented to compare the performance of the proposed finger selection algorithm
with those of the conventional and optimal schemes.Comment: To appear in the Proc. IEEE International Conference on Ultrawideband
(ICU-2005
SGD Frequency-Domain Space-Frequency Semiblind Multiuser Receiver with an Adaptive Optimal Mixing Parameter
A novel stochastic gradient descent frequency-domain (FD) space-frequency (SF) semiblind multiuser receiver with an adaptive optimal mixing parameter is proposed to improve performance of FD semiblind multiuser receivers with a fixed mixing parameters and reduces computational complexity of suboptimal FD semiblind multiuser receivers in SFBC downlink MIMO MC-CDMA systems where various numbers of users exist. The receiver exploits an adaptive mixing parameter to mix information ratio between the training-based mode and the blind-based mode. Analytical results prove that the optimal mixing parameter value relies on power and number of active loaded users existing in the system. Computer simulation results show that when the mixing parameter is adapted closely to the optimal mixing parameter value, the performance of the receiver outperforms existing FD SF adaptive step-size (AS) LMS semiblind based with a fixed mixing parameter and conventional FD SF AS-LMS training-based multiuser receivers in the MSE, SER and signal to interference plus noise ratio in both static and dynamic environments
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