In this paper, we present the findings of a study on the radio frequency (RF) signal switching and distribution techniques in a civil aviation aircraft. Using the Boeing Aircraft 777 as a model, method and mode of RF signal switching and distribution were investigated. The aim is to evaluate system performance and if possible determine methods of improvement. The performance of the system was measured in terms of savings in system parameters such as weight, size and length of the associated components. Instead of using coaxial cables or twisted pair wire for routing the RF signals, optical fibers cables were suggested as a method of improvement. During this study, the difficulty of achieving this objective became obvious due to the complexity of the problem. However, suggestions were made on possible methods of improvements.
In this paper, we present the performance of a multitone code division multiple access (MT-CDMA) system by analyzing the effect of coding. We use convolutionally coded substreams rather than serial-to-parallel converted data to modulate different subcarriers. The bit error rate bound for the decoding metric is derived. The coded and uncoded performance bounds are compared with respect to equal bandwidth, bit rate and other communication resources. We also present the performance trade-off for different coded modulation schemes. Our results indicate that the performance of an MT-CDMA is significantly improved when channel coding is applied.