Abstract-Theoretical results on the effect of antenna mutual coupling (MC) on capacity of multiple-input multiple-output (MIMO) wireless channels are presented in this paper with particular emphasis on the case of high signal to noise ratio (SNR) scenario. Two cases are considered, 1-channel capacity variations due to MC effect on correlation properties and target average receive SNR and 2-channel capacity variations due to MC effect on correlation properties at fixed average receive SNR. It is shown that the effect of MC on MIMO channel capacity can be positive or negative depending on the propagation environment spatial correlation properties and the characteristics of the transmitter and receiver MC matrices. Conditions where MC has positive and negative effects on MIMO channel capacity in the two considered cases are identified. Numerical results for half wavelength dipole antenna supporting the theoretical observations are presented.

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We surveyed the three main system aspects of smart antenna (SA) technology in wireless communications i.e. SA receiver, wireless network control and planning with SA. A classification of SA receivers and their algorithms is given in order to simplify orientation in a very large amount of structures and algorithms. We discuss system integration of SA receivers taking into consideration expected propagation conditions, user mobility and offered traffic. Several radio network planning and upgrading concepts associated with SA are evaluated. We describe possible radio networks architectures when smart antennas are used at the mobiles, base stations or at both ends. Radio network control functions with SA at the different layers are briefly examined. Existing experimental and commercially available SA and their performance are surveyed.

in this paper, the performance of IEEE 802.Ilb and 802.1 l g Wireless Local Area Networks (WLANs) performance under barrage jamming is evaluated theoretically and using measurements. Single WLAN ad-hoc link performance is measured when receiver station is jammed. W M link vulnerability assessment is based on throughput and Packet Error Rate (PER), which depends on d$-ferent Physical (PHY) layer characteristic. WLAN system is found to be more tolerant to narrow-band jamming than tu wideband-band jamming. In 802.1 I b WLAN, processing gain increases the tolerance to jamming whereus coding and diferent modulations are used to improve the link performance in 802.1 l g WLAN. Measured link throughputs are far from theuretical values, especially when high datu rate modes are used.

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