Impact of transmit antenna beamwidth for fixed relay links using ray-tracing and Winner II channel models

The BuNGee (Beyond Next Generation Mobile Broadband) project aims to improve the overall infrastructure capacity density of mobile networks to an ambitious goal of 1Gbps/km² in economical cellular deployment [1]. Its innovative architecture combines a number of technological paradigms, such as self-backhauling, joint design of access and backhaul, etc. It relies on a Hub Base Station (HBS) connected to the operator back-haul, distributed Access Base Stations (ABSs) connected to the HBS by a self-backhaul link on one side and to the Mobile Subscribers (MSs) on the other side. In this communication, we focus on the specificities of the propagation channel between HBS and ABS, as it is largely different from the channel between ABS and MS. Whilst a large amount of viable channel models, e.g. 3GPP, COST 273 and WINNER II, are available, they require some significant modifications to reflect the peculiarities of BuNGee architecture, in particular the transmit antenna specifications. Hence, pathloss models for the HBS-to-ABS link are investigated by a ray-tracing tool and simultaneously compared with the potential of WINNER II channel models. Furthermore, the impact of the transmitter´s narrow beamwidth is investigated and analyzed.