On the effect of Multiple Access Interference in a Space Time Spreading Time Hopping PPM UWB system

Vial, Peter James; Wysocki, Beata J.; Wysocki, Tadeusz A.; Ros, Montserrat; Stirling, David

doi:10.1016/j.compeleceng.2012.02.003

Cited by 3 publications

(17 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Such a situation is shown in Figure 2. The work in [2] has shown that under these conditions the received signal from User 2 will vary and this signal will tend to be unsynchronised resulting in Multiple Access Interference (MAI) at User 1's receiver due to User 2's transmission (the codes used were orthogonal, but as the received signal at User 1 from User 2 was unsynchronised then interference and degradation in the Bit Error Rate was experienced).…”

Section: Modeled Scenario For Ma1mentioning

confidence: 99%

“…The transmitted signal from each antenna is then radiated towards the receiver using different paths (the two transmit antennas need to be about ten wavelengths apart to be uncorrelated [4][5]). In the model here (and in [2]) there is no multipath, only the single path between each individual transmitter and b e receiver. Each of these paths will experience a different complex flat fading coefficient or gain during each symbol period.…”

Section: --mentioning

confidence: 99%

“…the previous study [2] the length of the orthogonal codes was N=128. While the inproved codes used in this sfudy had a chip length of N=32.…”

Section: --mentioning

confidence: 99%

“…Previous work has shown that the performance of a Space Time Spreading (STS) [2] indicated that better sets of orthogonal codes can be found which mitigate the effects of ~u l t i~l e Access Interference (MAI) [3]. These codes are here applied to a Space Time where (' )" stands for the transpose and n is a Spreading System as proposed in [ l ] and used in [2].…”

Section: Introductionmentioning

confidence: 99%

“…These codes are here applied to a Space Time where (' )" stands for the transpose and n is a Spreading System as proposed in [ l ] and used in [2]. …”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Space time spreading with modified Walsh-Hadamard sequences

Vial

Wysocki

Raad

et al.

Eighth IEEE International Symposium on Spread Spectrum Techniques and Applications - Programme and Book of Abstracts (IEEE Cat.

View full text Add to dashboard Cite

Previous work has shown that the performance of a Space Time Spreading (STS) system using walsh codes with two transmit antennas at the Base Station (BS) is degraded in the presence of mutual interference from adjacent sectors in the same cell. In this paper we use Modified Walsh-Hadamard sequences exhibiting improved cross-correlation performance, which potentially mitigates the effects of MA1 (Multiple Access Interference). The presented study also looks at variation of sets of different Modified WalshHadamard codes being used by the adjacent interferer, with a hundred randomly selected pairings being chosen, as well as the case where one set of alternate codes is used. It is shown using simulation that significant improvement of the order of 0.5-2 dB B possible using these sequences instead of the standard Walsh code previously proposed.where and c2 are the orthogonal spreading codes used. In

show abstract

Section: Modeled Scenario For Ma1mentioning

confidence: 99%

Section: --mentioning

confidence: 99%

“…the previous study [2] the length of the orthogonal codes was N=128. While the inproved codes used in this sfudy had a chip length of N=32.…”

Section: --mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…These codes are here applied to a Space Time where (' )" stands for the transpose and n is a Spreading System as proposed in [ l ] and used in [2]. …”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Space time spreading with modified Walsh-Hadamard sequences

Vial

Wysocki

Raad

et al.

Eighth IEEE International Symposium on Spread Spectrum Techniques and Applications - Programme and Book of Abstracts (IEEE Cat.

View full text Add to dashboard Cite

show abstract

On the effects of spreading sequences over MIMO systems

Liu

Stirling

Tran

et al. 2013

2013, 7th International Conference on Signal Processing and Communication Systems (ICSPCS)

Self Cite

View full text Add to dashboard Cite

In this paper, we develop a Software Defined Radio (SDR) test bed to evaluate the Multiple Access Interference (MAI) effects over SISO and 2 x 1MIMO systems. It can be observed that under asynchronous transmissions, the Gold code leads to the best performance over both systems due to the fact that it has the best correlation properties. We also find the MAI effects in terms of the spreading sequences pairs on MIMO-STS systems. We propose a criterion for selecting promising spreading sequences for MIMO systems. Based on the measured results, we identify pairs of spreading sequences which have improved BER compared to other pairs in the same set of spreading sequences. We infer that the choice of spreading sequence pairs in a MIMO-STS system in the presence of MAI sources is an important factor to be considered.

show abstract

A promising set of spreading sequences to mitigate MAI effects in MIMO STS systems

Tran

Premaratne

et al. 2015

2015 9th International Conference on Signal Processing and Communication Systems (ICSPCS)

Self Cite

View full text Add to dashboard Cite

Multiple input, Multiple output space time spreading (MIMO STS) system is a scheme which can provide full diversity gain without extra resource requirements. However, its performance degrades significantly when multiple access interference (MAI) occurs. In order to mitigate MAI effects, we propose a criterion to build a promising set of combination of spreading sequences for users. Simulation results show that the average BER performance of users using this promising set is about thirty percent lower than that of users using another set in case of 64 chip length Walsh-Hadamard code. Abstract-Multiple input, Multiple output space time spreading (MIMO STS) system is a scheme which can provide full diversity gain without extra resource requirements. However, its performance degrades significantly when multiple access interference (MAI) occurs. In order to mitigate MAI effects, we propose a criterion to build a promising set of combination of spreading sequences for users. Simulation results show that the average BER performance of users using this promising set is about thirty percent lower than that of users using another set in case of 64 chip length Walsh-Hadamard code.

show abstract

On the effect of Multiple Access Interference in a Space Time Spreading Time Hopping PPM UWB system

Cited by 3 publications

References 19 publications

Space time spreading with modified Walsh-Hadamard sequences

Space time spreading with modified Walsh-Hadamard sequences

On the effects of spreading sequences over MIMO systems

A promising set of spreading sequences to mitigate MAI effects in MIMO STS systems

Contact Info

Product

Resources

About