A real-time DOA-based smart antenna processor
A real-time DOA-based smart antenna processor
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DOI：
10.1109/tvt.2002.801737
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发表时间：
2002-11-01
影响因子：
6.8
通讯作者：
Bonek, E
中科院分区：
文献类型：
--
作者：
Kuchar, A;Tangemann, M;Bonek, E
我们为基于波达方向的智能天线GSM 1800基站设计、构建和测试了一个实时处理器，该基站具有8个半波长间隔的天线单元。其处理步骤包括波达方向(DOA)估计、用户识别、跟踪、波束形成和信号重构。我们证明，DOA估计的精度并不是首要问题，但稳健性是首要考虑的问题。这可以通过一个新的参数来评估，即估计范围。仅跟踪可靠的用户DOA，增加了对干扰的稳健性。我们的跟踪概念与频率、跳跃兼容。我们通过统计载波干扰比(C/I)和信噪比(SNR)的增益来量化智能天线的好处，两者都是用实际传输的数据在90%或90%的水平上测量的。在用户和干扰信号具有较大角度扩展和重叠的城市环境中，C/I增益高达18分贝。干扰置零仅略微增加C/I增益，但增强了抗角扩展的稳健性，特别是在应用宽零点的情况下。将波束形成和分集对信噪比的贡献分开，可以更好地了解算法的运行方式。在上行链路中，处理器可以利用角度分集。整个处理步骤在不到1ms的时间内完成，证明了复杂的基于DOA的智能天线处理是实时可行的。我们的解决方案不需要对GSM标准进行任何更改。
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-to-interference ratio (C/I) and in signal-to-noise ratio (SNR), both measured at the 90 or 90% 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.