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Multiple antenna time reversal transmission in ultra-wideband communications
- in Proc. of IEEE Globecom. IEEE
, 2007
"... Abstract — In this paper we study the multiple antenna time reversal downlink transmission in an ultra-wideband (UWB) communication system which consists of access points and users. The access point has multiple antennas and the user has a single antenna. We design the UWB beamformer that focuses on ..."
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Cited by 7 (3 self)
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Abstract — In this paper we study the multiple antenna time reversal downlink transmission in an ultra-wideband (UWB) communication system which consists of access points and users. The access point has multiple antennas and the user has a single antenna. We design the UWB beamformer that focuses on the intended user while minimizing its interference on unintended users and eavesdropping access points. We show that the designed UWB beamformer is equivalent to the time reversal focusing and nulling schemes and yields better performance than the conventional delay line wideband beamformer. We verify our results using experimentally measured electromagnetic data in an indoor environment. I.
Genetic algorithm based equalizer for ultra-wideband wireless communication systems
- IEICE Transactions on Communications
, 2010
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Multipath Delay Profile Acquisition for Ultrawideband PPM Systems
"... The acquisition of a multipath channel profile (including the leading delay) for ultra-wideband pulse position modulation (PPM) communication systems is considered in the limit of large bandwidth. Optimal acquisition is defined by the maximum likelihood detector whose performance can be assessed via ..."
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The acquisition of a multipath channel profile (including the leading delay) for ultra-wideband pulse position modulation (PPM) communication systems is considered in the limit of large bandwidth. Optimal acquisition is defined by the maximum likelihood detector whose performance can be assessed via order statistics. Four channel scenarios are examined: deterministic or Gaussian channel taps; uniform or exponential power delay profiles. For these four channels, the rate of growth for the multipath as a function of bandwidth which leads to acquisition failure is determined. Acquisition is not even partially possible on multipath channels with deterministic path amplitudes, if the number of paths diverges too fast. Furthermore, if the number of independent Gaussian paths increases without bound, but slower than the bandwidth, then the system cannot even partially acquire in the limit. These negative results are shown for somewhat idealized environments, implying that multipath delay profile acquisition will fail under more realistic conditions. I.
Measurement and Analytical Study of the Correlation Properties of Subchannel Fading for
, 2013
"... Abstract—The new multichannel/multicarrier technologies can potentially support much higher data rates in mobile multiple-access environments, such as carrier aggregation (CA) defined in the fourth-generation Long-Term Evolution Advanced enhance-ment. The correlation properties of noncontiguous subc ..."
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Abstract—The new multichannel/multicarrier technologies can potentially support much higher data rates in mobile multiple-access environments, such as carrier aggregation (CA) defined in the fourth-generation Long-Term Evolution Advanced enhance-ment. The correlation properties of noncontiguous subchannels are critical for the performance of CA, including cell coverage, frequency diversity, and channel state estimation. This paper has studied the correlation of the large-scale fading (LSF) and small-scale fading (SSF) of arbitrarily separated subchannels by realistic channel measurement and analytical modeling. We first obtain the subchannel correlation from the ultrawideband (UWB) channel measurement. This new approach avoids probing multiple subchannels simultaneously with channel sounders, which would be prohibitively complicated. The cross correlation of two distinct subchannels and the autocorrelation of a single subchannel are
