Code Shift Keying Modulation For Low-Rate UWB Communications Under Dense Multipath

Fixed guard times considered for the physical layer of the IEEE 802.15.4a standard (low-rate Wireless Personal Area Networks) cause user asynchronism-dependent collisions that affect the instantaneous bit-error-rate (BER) and packet-error-rate (PER) performances in the presence of simultaneously operating piconets (SOPs). Using code shift keying (CSK), the location of the guard times can be randomized yielding the collision event independent of user asynchronism. In this paper, CSK modulation is adopted for the physical layer of the IEEE 802.15.4a standard with a special code design technique, and it is shown that the proposed implementation of CSK stabilizes the instantaneous BER and PER values. Stabilizing the instantaneous BER and PER values prevents worst-case scenarios, where many packets may be lost due to user asynchronism-dependent collisions, and should be carefully considered for real system implementation.