Anil Agiwal

Comparison Analysis of Outdoor Channel Characteristics at 28 GHz and 2 GHz Using 3D Ray-Tracing Technique

Broadband wireless systems operating in millimeter wave (mmWave) frequency band has been used for short-range wireless communication and point-to- point wireless backhaul. Due to lack of research work on outdoor radio propagation characteristics in mmWave frequency band, the question of feasibility of cellular communication including long-range and non-line of sight (NLoS) environments in mmWave frequency band is unanswered. In this paper, we investigate the radio propagation characteristics at 28 GHz and 2 GHz using 3D ray-tracing simulation based on Manhattan-like grid model. LoS and NLoS results of outdoor radio propagation characteristics considering beamforming effects at 28 GHz are provided. Results of 2 GHz in the same geometry are also provided. In LoS environment, the radio propagation with 25 dBi beamforming gain at 28 GHz has similar characteristics with 2 GHz. In NLoS environment, even if the transmitter has 25 dBi beamforming gain at 28 GHz, the received power is 10 to 25 dB lower than 2 GHz. The received power loss because of narrow beam usage at 28 GHz is negligible in both LoS and NLoS environments.

Performance analysis of DRX mechanism considering analogue beamforming in millimeter-wave mobile broadband system

To meet the explosive growth of mobile traffic, it is necessary to guarantee high data rate in todays communication system. One of the methods to support high data rate is to use wide bandwidth (spectrum). Due to the limitation of frequency spectrum for the commercial usage, we choose millimeter-Wave (mmW) band of 30GHz and exploit analogue beamforming technique, focusing electro-magnetic wave energy at a certain direction, not an omni-direction. In the analogue beamforming technique, beam selection is required so that base station (BS) and mobile station (MS) communicate with the best beam each other and this procedure is performed periodically for the selected beams not to be mis-aligned. To extend battery lifetime of user equipment, current broadband system such as 3GPP LTE/LTE Advanced adopts discontinuous reception (DRX) which the new mmW system needs too. Therefore, we propose the DRX mechanism considering analogue beamforming technique and analyze the performance of the system varying parameters of beam selection and DRX according to the given beam pattern, traffic model and movement of MS.