| 1. |
- Mohammed, Abbas, et al.
(author)
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Equalisation Techniques for Satellite-UMTS
- 1998
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Conference paper (peer-reviewed)abstract
- Adaptive equalization is a key issue to improve the performance of satellite mobile communication systems. S-UMTS transmission channels generate distortions due to multipath propagation and the use of nonlinear power amplifiers, such as traveling wave tubes or solid state power amplifiers, near their saturation region. These distortions are time varying and therefore need adaptive processing. This paper will present conventional and blind equalisation algorithms and investigate their suitability and performance in an electromagnetically crowded and hostile conditions encountered in S-UMTS.
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| 2. |
- Nordholm, Jörgen, et al.
(author)
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Blind Adaptive spatial Equalisation in S-UMTS-system
- 1999
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Conference paper (peer-reviewed)abstract
- Today there is an increasing demand for a higher data rate in both the existing and future mobile communication system. With higher data rate, the InterSymbol Interference (ISI) problem will also increase. In this paper, a Spatial Normalised Adaptive Constant Modulus Algorithm (SA-NCMA) equaliser will be presented that will compensate for the ISI problem.
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| 3. |
- Claesson, Ingvar, et al.
(author)
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A Multi-DSP implementation of a Broadband Adaptive Beamformer for use in a Hands-free Mobile Radio Telephone
- 1991
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In: IEEE Transactions on Vehicular Technology. - New York : Institute of electrical and electronics engineers. - 0018-9545. ; 40:1, s. 194-202
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Journal article (peer-reviewed)abstract
- An implementation of a broadband adaptive array on a multiprocessor digital signal processing (DSP) system for use in a hands-free mobile radio telephone is described. This implementation of a five-microphone adaptive Griffiths-Jim array can handle FIR filters with up to 128 taps behind each microphone at a sampling rate of 8 kHz. The filter structure makes it possible to combine an adaptive array with a noise canceler. The near-field problem has been solved by using focusing, a speech-controlled adaptive algorithm, and a short hourglass. Preliminary measurements indicate a considerable potential for this technique in hands-free mobile telephony. The array gives a 20-30-dB suppression of a broadband jammer covering 300-1100 Hz, even with three reflecting walls surrounding the microphone.
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| 4. |
- Claesson, Ingvar, et al.
(author)
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A Spatial Filtering Approach to Robust Adaptive Beamforming
- 1992
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In: IEEE Transactions on Antennas and Propagation. - New York : Institute of electrical and electronics engineers. - 0018-926X. ; 40:9, s. 1093-1096
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Journal article (peer-reviewed)abstract
- This communication treats the problem of controlling the superresolution in adaptive beamformers. A straightforward method is presented that works for both narrow-band and broad-band arrays. The method is based on forming the blocking matrix in a general sidelobe canceller (GSC) structure using a spatial FIR filter. The suppression of this spatial filter and the implicit noise of the leaky (LMS) algorithm together determine the beamformer.
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| 5. |
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| 6. |
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| 7. |
- Claesson, Ingvar, et al.
(author)
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Car Performance of an Adaptive Microphone Array
- 1992
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Conference paper (peer-reviewed)abstract
- Hands free input of mobile telephones is often almost impossible due to the noise situation in the car and the channel quality. The authors present a method to enhance the quality using an adaptive microphone array. Measurements show an improvement of the input with approximately 10 dB. Tape results are available for subjective evaluation.
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