Indoor wireless communication has recently drawn the attention of many researchers because of its significant advantages over conventional cabling: allowing mobility of users, time and cost saving, office arrangements and physical moves can be handled with minimal disruption of work, and temporary services can be provided. The average bit error probability in a Rician fading channel is evaluated for two types of spread spectrum systems using differential phase shift keying modulation: frequency hopping and hybrid frequency hopping / direct sequence. Also the influence of diversity, as a means to enhance the performance of the system has been investigated.