Investigating the effects of antenna directivity on wireless indoor communication at 60 GHz

Abstract

Tel: +44 (0) 1 17 954 5 169, Fax: +44 (0)117 954 5206 ABSTRACT This paper investigates the nature of the indoor radio channel at 60GHz, with regard to its use for future high bitrate broadband wireless networks. It is proposed that, for operation in the millimetre-wave indoor channel, directional antennas can be used to mitigate multi-path effects, thus reducing the need for complex equalisation or multi-carrier techniques. An image based, ray-tracing prediction model is used to study the channel Characteristics and to analyse the variation in received power, RMS delay spread and k-factor within a typical operating environment. The performances of different antenna combinations are investigated and narrowbeam, suitably aligned antennas are shown to reduce received delay spread for both LOS and non-LOS locations.The effects of non-optimal antenna alignment are observed, and system outage is determined for certain system design criteria. The results suggest that it will feasible to combat multi-path effects using switched-beam directional antennas.

Blockage and directivity in 60 GHz wireless personal area networks: from cross-layer model to multihop MAC design

“…Diffraction due to obstacles: We use a simple geometric model to estimate the diffraction loss along the LOS path between two nodes, taking into account the node placements, the locations and dimensions of obstacles, and the room dimensions. We neglect the contribution from the reflected signals to the received signal power; narrow beam directional antennas along the LOS direction substantially reduce the contribution of reflected multipath components [23], [32], [33], [36]. We make the following simplifying assumptions in modeling obstacles:…”

“…Measurement campaigns in indoor environments include [20]- [29]. For typical indoor environments with omnidirectional antennas, specular reflections from surfaces are dominant contributors to the received signal power as compared with diffraction or scattering [24], [30]- [32]. Since the path that is the strongest in such a setting is the LOS path (if it is not blocked), this motivates restriction to LOS for maximizing power efficiency.…”

“…Since the path that is the strongest in such a setting is the LOS path (if it is not blocked), this motivates restriction to LOS for maximizing power efficiency. The reduction of multipath for directional mm wave links [23], [32], [33] means that link budget calculations for a simple additive white Gaussian noise channel model are reasonably accurate for a directional LOS link. The susceptibility of mm wave links to blockage due to their weak diffraction characteristics is well known [23], [34], and the effect of human movement is investigated in [35], [36], but their impact on the network performance has not been studied previously.…”

Improving and Extending Indoor Connectivity Using Relay Nodes for 60 GHz Applications

“…Since there is only one link in the first case then it's PDF equal , but for the second case we need the maximum PDF between the two links which is: (8) Since and are equal, then can be used as a PDF for both cases. By taking the extreme values of in the two cases and then: (1) for first case.…”

“…So, interference mitigation techniques are needed [7]. Directional antenna proposed to overcome high values of FSPL in [8], but the signals with the proposed technique can be easily blocked by any obstacle. Beamforming or beam steering is proposed in [9] to overcome blockage in directional antennas and enhance their performance in 60 GHz system.…”