This paper proposes a relay channel model which takes into account the influence of relay location and antenna configuration. Simulation results show that when relay is in the line-of-sight (LOS) propagation environment, the channel capacity will degrade. To improve the performance of the channel, water-filling (WF) algorithm is used to allocate the power, simulation results shows that the WF-based relay channel outperforms the uniform power allocation channel. The radiation pattern of the relay antenna is also an importance factor which affects the channel capacity in this case. The widely used Rayleigh channel model overestimates the performance of the channel compared with our model when the location of the relay is not in the scenario where Ricean K-factor is zero. Measurements have been done at 2.53 GHz to investigate the above-rooftop and ground-level relay channels. Results indicate that above-rooftop deployment is very efficient to improve the capacity and coverage.