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Smart antenna technology is one of key technologies used in TD-SCDMA system. By using DSP algorithms and dynamically generating the beam pattems, smart antenna can greatly reduce the interference and increase the system capacity. In this paper, the concept of smart antenna is presented and a novel detection technique called joint space-time processing based on smart antenna is described. Simulation results on the uplink performance of TD-SCDMA in macrocell environment are also included in the paper. It can be seen that smart antenna system has much better performance than without smart antenna system and can meet the requirements of the 3rd generation system.

Abstract. Due to the increasing number of users in mobile communications and the demand for mobile multimedia services with high data rates, third generation mobile radio systems are currently one ofthe key communication technologies in research, development, and international standardization bodies. Smart antennas can be used to increase thc capacity of wireless communication systems even further. TDD systems are particularly attractive for the employment of smart antennas, since the channel information (e.g.. in terms of spatial covariance matrices) estimated on the uplink can be used directly for downlink beamforming. In this paper, we discuss efficient uplink and downlink processing techniques with smart antennas for UTRA TDD, the TDD mode of third generation mobile radio systems that is based on TD-CDMA. On the uplink, joint space-time processing is used to eliminate cochannel interference created by other users that transmit on the same frequency and in the same time slot. These joint detection techniques are efficiently implemented in the frequency domain. On the downlink, the data is only tnnsmitted in the direction of the desired mobile user while interference in the direction of cochannel users is avoided. Moreover, short-rerm spatial channel estimates can be improved by projecting them into the dominant subspace of the long-term spatial covariance matrix. System level simulations have been performed to evaluate the gain in spectral efficiency (available bit rate per bandwidth per cell) if simple downlink beamforming techniques are used at the base stations. There is a two-to three-fold spectral efficiency gain if antenna arrays of . \ I = 8 elements are deployed in a sectorized macro-cellular environment.

Abstract. Using adiabatic CMOS logic instead of the more traditional static CMOS logic can lower the power consumption of a hardware design. However, the characteristic differences between adiabatic and static logic, such as a fourphase clock, have a far reaching influence on the design itself. These influences are investigated in this paper by adapting a systolic array of CORDIC devices to be implemented adiabatically.We present a means to describe adiabatic logic in VHDL and use it to define the systolic array with precise timing and bit-true calculations. The large pipeline bubbles that occur in a naive version of this array are identified and removed to a large degree. As an example, we demonstrate a parameterization of the CORDIC array that carries out adaptive RLS filtering.

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