Delay spread measurements on a wideband MIMO channel at 3.7 GHz

Kepler, J.F.; Krauss, T.P.; Mukthavaram, S.

doi:10.1109/vetecf.2002.1040671

Cited by 24 publications

(14 citation statements)

References 1 publication

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“…While, in practical systems, the chip-pulses might be spaced farther apart, complexity precluded us from 11 Here we assume a uniform angle-of-arrival distribution; practical systems may deviate from this assumption. doing so.…”

Section: Numerical Resultsmentioning

confidence: 99%

“…By convention, we assume that the shortest path has time delay of zero. Some channels may be considered sparse, such that L (a, τ ) is non-zero on a small fraction of the set Ω [11]. We define the effective delay spread τ sup to be the measure of the non-zero lag support.…”

Section: B Wideband Channel Representationmentioning

confidence: 99%

“…However, vehicular channels are often sparse, as shown in [11]. For example, in 95% of measured channels only 5 rays were significant 4 , while in 79% of measured channels only 2 rays were significant.…”

Section: B Wideband Channel Representationmentioning

confidence: 99%

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Joint scale-lag diversity in wideband mobile direct sequence spread spectrum systems

Margetts

Schniter²,

Swami³

2007

IEEE Trans. Wireless Commun.

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Abstract-We consider the effect of mobility on a wideband direct sequence spread spectrum (DSSS) communication system, and study a scale-lag Rake receiver capable of leveraging the diversity that results from mobility. A wideband signal has a large bandwidth-to-center frequency ratio, such that the typical narrowband Doppler spread assumptions do not apply to mobile channels. Instead, we assume a more general temporal scaling phenomenon, i.e., a dilation of the transmitted signal's time support. Based on a uniform ring of scatterers model, we determine that the wideband scattering function, which quantifies the average scale spreading, has a "bathtub-shaped" scale profile. We compare the performances of a scale-lag Rake and a frequency-lag Rake, each capable of leveraging the diversity that results from mobility. Such analysis applies, for example, to ultra-wideband (UWB) radio frequency channels and underwater wideband acoustic channels.Index Terms-Mobile wireless communication, scale-lag diversity, spread spectrum, wideband systems.

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Section: Numerical Resultsmentioning

confidence: 99%

Section: B Wideband Channel Representationmentioning

confidence: 99%

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Joint scale-lag diversity in wideband mobile direct sequence spread spectrum systems

Margetts

Schniter²,

Swami³

2007

IEEE Trans. Wireless Commun.

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“…For example, Bell Labs took a capacity survey in Manhattan by using a 16 Tx and 16 Rx narrowband channel sounder with a bandwidth of 32 kHz [3]. The orthogonal frequency division multiplexing (OFDM) technology was used to build a 2 Tx and 2 Rx wideband MIMO channel system [4], [5]. Some European researchers built the MIMO channel testbed by using a fast-switch to multiplex a pseudo parallel signal to antennas [6].…”

Section: Introductionmentioning

confidence: 99%

Delay Spread Characteristics of Wideband MIMO Channels Based on Outdoor Non-Line-of-Sight Measurements

Yang

Zhang

2007

IEEE GLOBECOM 2007-2007 IEEE Global Telecommunications Conference

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This paper presents the delay spread characteristics based on the measurements of the wideband multipleinput multiple-output radio channels in outdoor environments. Measurement data were collected by a channel testbed which consists of four transmitters and eight receivers, and operates at a carrier frequency of 1.8 GHz with a bandwidth of 2.5 MHz. The four transmitting antennas and eight receiving antennas can work simultaneously. The experiments were originally conducted within the J. J. Pickle Research Campus, University of Texas at Austin. Based on the measurement data in the non-line-of-sight environments, the channel features such as multipath intensity profiles, root-mean-square delay spreads and their distributions were examined. It was found that the empirical probability density function of the rms delay spread in the non-line-of-sight MIMO channels roughly follows Gaussian distribution.

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“…Section II considers both the feedback report rates required to track the time-variations of the channel and, based on a widely accepted speed distribution [12], proposes a scheduling interval (e.g., frame duration) and speed-based report format that balances achievable gains with the amount of feedback. Section III examines the frequency selectivity observed in an experimental 20 MHz system [13] for determining a subcarrier grouping bin size to balance frequency variation within a bin with feedback bandwidth per report. Turbo code simulations are provided to show that the small variations over a reasonably-sized bin will not degrade performance significantly from static results.…”

Section: Introductionmentioning

confidence: 99%

Multi-dimensional adaptation and multi-user scheduling techniques for wireless OFDM systems

Classon

Sartori

Nangia

et al.

IEEE International Conference on Communications, 2003. ICC '03.

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This paper considers techniques to increase the performance of a broadband wireless OFDM system through adaptation in both the time and frequency domains. System throughput estimates are provided for frequency non-selective coding (coding for frequency diversity across subcarriers) and frequency selective coding (e.g., DSL) for single antenna, Alamouti, and selective closed-loop MIMO configurations. Additional gains from performing multi-user frequency-domain scheduling are achieved and determined using proportional fair and maximum (subcarrier) C/I schedulers. The performance gains of multi-dimensional adaptation and scheduling techniques are contrasted with the amount of feedback required. Measured data from a 20 MHz experimental system and turbo coding simulations are used to estimate the size of each feedback report, and an accepted user speed distribution is used to estimate an appropriate feedback rate.

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Delay spread measurements on a wideband MIMO channel at 3.7 GHz

Cited by 24 publications

References 1 publication

Joint scale-lag diversity in wideband mobile direct sequence spread spectrum systems

Joint scale-lag diversity in wideband mobile direct sequence spread spectrum systems

Delay Spread Characteristics of Wideband MIMO Channels Based on Outdoor Non-Line-of-Sight Measurements

Multi-dimensional adaptation and multi-user scheduling techniques for wireless OFDM systems

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