Real-time smart antenna processing for GSM1800 base station

Kuchar, A.; Taferner, Manfred; Tangemann, M.; Hoek, Cornelis; Rauscher, W.; Strasser, Martin; Pospischil, Günther; Bonek, E.

doi:10.1109/vetec.1999.778239

Cited by 8 publications

(6 citation statements)

References 13 publications

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“…We measured the estimate variation in a controlled LOS environment [13]. When a discrete wave was incident from broadside the measured estimate variation was smaller than 1 for an input SNR larger than 0 dB, but decreased monotonically to the order of some hundreds of a degree with increasing SNR up to 40 dB, for all three estimators (see Fig.…”

Section: A Doa Estimation Accuracymentioning

confidence: 99%

“…In this paper, we focus on measurements demonstrating interference reduction. In noise limited environments, a diversity gain was achieved [12].…”

Section: System Conceptmentioning

confidence: 99%

“…A larger CAS will again degrade the beamforming gain, but not the diversity gain. 12 The term cluster is borrowed from channel modeling. In the geometrybased stochastic channel model (GSCM) [18], finite angular spread is modeled by local scatterers around the MS.…”

Section: Appendix I Component Angular Spreadmentioning

confidence: 99%

“…In this work both uplink and downlink are treated in a single homogenous directions-of-arrival (DOA)-based approach. In Section II we present the developed GSM1800 smart antenna base station [13], [14]. Its heart is the real-time Adaptive Antenna Array Processor A P (Section III).…”

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confidence: 99%

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A real-time DOA-based smart antenna processor

Kuchar

Tangemann

Bonek

2002

IEEE Trans. Veh. Technol.

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Abstract-We designed, built, and tested a real-time processor for a direction-of-arrival-based smart antenna GSM 1800 base station with eight half-wavelength spaced antenna elements. Its processing steps include direction-of-arrival (DOA) estimation, user identification, tracking, beamforming, and signal reconstruction. We demonstrate that the accuracy of DOA estimation is not of primary concern, but the robustness is. This can be assessed by a new parameter, the estimation range. Tracking of reliable user DOAs only, increases the robustness against interference. Our tracking concept is compatible with frequency hopping. We quantify the benefits of smart antennas by the statistics of the gain in carrier-tointerference ratio (C/I) and in signal-to-noise ratio (SNR), both measured at the 90 or 99% levels with actual transmitted data. In an urban environment with large angular spread and overlap of user and interferer signals, the C/I gain is as high as 18 dB. Interferer nulling increases the C/I gain only slightly, but enhances robustness against angular spread, particularly if broad nulls are applied. Separating SNR gain in its contributions due to beamforming and diversity gives valuable insight into the way of operation. In uplink, the processor can exploit angular diversity. The entire suite of processing steps is done within less than 1 ms, demonstrating that sophisticated DOA-based smart antenna processing is feasible in real time. Our solution does not require any change in the GSM standard.Index Terms-Angular diversity, carrier-to-interference ratio (C/I) improvement, component angular spread, direction-of-arrival estimation, smart antenna, wireless communications.

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Section: A Doa Estimation Accuracymentioning

confidence: 99%

“…In this paper, we focus on measurements demonstrating interference reduction. In noise limited environments, a diversity gain was achieved [12].…”

Section: System Conceptmentioning

confidence: 99%

Section: Appendix I Component Angular Spreadmentioning

confidence: 99%

mentioning

confidence: 99%

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A real-time DOA-based smart antenna processor

Kuchar

Tangemann

Bonek

2002

IEEE Trans. Veh. Technol.

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“…OST of the beamforming techniques that have been applied to wireless communication systems have been designed for global systems for mobile communications (GSM) and time-division multiple access (TDMA)-based cellular systems [1], [2]. These beamforming techniques cannot be directly applied for direct sequence (DS) code division multiple access (CDMA) systems.…”

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confidence: 99%

Computationally efficient smart antennas for CDMA wireless communications

Song

Kwon

Min³

2001

IEEE Trans. Veh. Technol.

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Abstract-The analysis in this paper concerns the performance of smart antenna algorithms when used in code-division multiple access (CDMA) wireless communication systems. Complex pseudonoise (PN) spreading, despreading, and pilot-aided channel estimates in the cdma2000 reverse link are some of major characteristics that are different from those in the IS-95 CDMA systems. These different features are included in our analysis. Four computationally efficient smart antenna algorithms are introduced: 1) smart antenna based on maximum output power criteria without lagrange multiplier; 2) smart antenna based on maximum signal-to-interference-plus-noise output power ratio (SINR) criteria with eigenvector solution; 3) smart antenna based on maximum SINR output criteria without eigenvector solution; 4) more simplified smart antenna based on maximum SINR output criteria without eigenvector solution. Algorithms (1) and (4) require only 4 computational instruction cycles per snapshot where is the number of antenna array elements. Algorithms (2) and (3) require 2 and (4 + 2 2 ) operations per snapshot, respectively. These computational loads are significantly smaller than those of typical eigenvalue decomposition blind detection approaches. Bit error rates (BERs) resulting from these algorithms are evaluated through simulation. Double spike power delay profile with equal or unequal power is used. Also, a cluster of interfering users and scattered interference users are considered. For BER comparisons, antenna diversity using equal gain combining is also analyzed. The four smart antenna algorithms show significant capacity improvement compared to the antenna array diversity using equal gain combining under the double spike power delay profile with equal power and scattered interference environments.Index Terms-Adaptive array antenna, code division multiple access (CDMA), mobile fading environment, multiple access interference, smart antenna, wireless communications.

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