Bounds on the capacity of slow frequency selective fading channels

Although communication systems are often analyzed under the assumption of prior knowledge of the channel, this is rarely the case in practical systems, which usually need to estimate the channel from the received communication signal. The analysis of channel capacity in the absence of prior channel knowledge had gained increasing interest in recent years, but this capacity is not yet known for the general case. In this paper we derive tight bounds on the capacity of the channel in the case of slow frequency selective fading channels with peak power constraint. We also show that in this case, a system that employs truncated Gaussian signaling and minimum Euclidean distance receiver can achieve information rates which are very close to the channel capacity.