Duty Cycle Division Multiplexing Technique for Wireless Communications

Abstract

A new multiplexing technique which is called duty cycle division multiplexing (DCDM) is presented in this paper. Theoretical and simulation studies have been carried out to evaluate the performance of this technique based on the signal energy and symbol error rate (SER). A wireless channel based on free space propagation model is considered for the simulation study. Two modulation schemes of PSK and QAM are used to evaluate the technique, against the number of users and data rates. Also, the performance of the multiplexing technique is compared with the conventional time division multiplexing (TDM) technique as well as with the multilevel M-ary signaling. The study shows that the energy per bit in the DCDM technique, unlike that of the TDM technique increases with the number of users. The simulation results correspond with the theoretical study in which the DCDM technique has better SER than that of TDM.

Improvement of Decision Making Protocol for Duty Cycle Division Multiplexing (DCDM) System

“…Quantification of valid signals are done by the Clock and Data Recovery (CDR) module. Meanwhile, the invalid signals are further evaluated using a new protocol using a function of metric below (1) where A denotes a total amplitude of signal changes, S number of slot change, , distance between slots and , the probability of amplitude at particular slots being '0', '1' ,'2' or '3'. The probabilities are shown in Table I below The detailed implementation of the decision making protocol can be seen in the algorithm below Ts=1; while true wait for Ts = number of samples/bits receive signal spectrum/(n+1) for user n = 1:3 implement decide data for user, n end Ts = Ts + number of samples/bits end…”

“…Recent progress in Duty Cycle Division Multiplexing (DCDM) technique has shown the improvement of optical channel bandwidth utilization [1], [2], [3], [4], [5], [6]. Moreover, the use of different duty-cycles is considered as another advantage of DCDM.…”

“…It is established that the longer duty-cycle over a signal period, the more tolerable it is to errors. Thus, the user's signal of higher slot number will be less affected by the errors [1].…”