Abstract-This paper investigates diversity for dual-antenna systems operating in indoor environments. First, an approximated equation of the diversity gain is derived for different combining techniques. These theoretical results show that the two-term approximation, as generally used in the literature [5], is too rough an estimate. Consequently, a new six-term approximation is derived. Next, it is demonstrated by a comparison of theoretical and experimental diversity gain values that, due to mutual coupling between the two antennas in practice, the diversity gain will not approach 0 dB if the distance between the two antennas approaches zero. Finally, it is concluded from measurements at 900 MHz that antenna-pattern diversity is a better choice than space diversity for use at handhelds.

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International audienceModern cellular base stations are becoming increasingly multi-carrier and multi-standard/multi-mode for improved efficiency and manageability. Primary among prospective multi-mode base station deployments will be those that are reconfigurable but also capable of simultaneous transmission of several types of cellular signals. However, unified or convergent-transmitter design is challenging, particularly with the small specified tolerances for signal distortion. We present an analysis of the Error Vector Magnitude (EVM) specifications for GSM/EDGE, UMTS and LTE, based on simulated EVM sensitivity to various distortions, focusing on a convergent transmit chain for multi-standard, multi-carrier macro-cell base stations. These analyses illustrate a method of deriving preliminary radio transmitter performance (phase noise, IQ imbalances, noise floor etc.) requirements, alongside helping to expose bottlenecks and performance tradeoffs necessary to optimize power consumption. A preliminary distribution of distortion or performance among the blocks is presented, to achieve the less than 5% multi-mode EVM budget, for worst-case scenarios

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