It is argued that the "rightful purpose" of a CDMA modulation system is to create a good channel for the coding system. This viewpoint leads to a precise formulation of energy efficiency and a novel formulation of bandwidth occupancy as normalized Shannon bandwidth. Various modulation/coding architectures are formulated and compared. It is shown that it is possible to design systems in such a w...

In recent years, various chaos based modulation schemes were evolved, of which the CS-DCSK modulation technique provides better BER performance and bandwidth efficiency, due to its code domain approach. The QCSK modulation technique provides double benefit: higher data rate with similar BER performance and same bandwidth occupation as DCSK. By combining the advantage of code shifted differentia...

A new orthogonal multicarrier bandwidth modulation (OMBM) scheme is proposed in this paper. The distinct feature of this scheme is that the frequency domain data is used to decide the number of orthogonal subcarriers for wireless transmissions. Different bandwidth of the OMBM symbol in the time domain reflects on the different data in the frequency domain. A Discrete Fourier Transform (DFT) bas...

Three experimental paradigms were used to specify the auditory system’s frequency selectivity for amplitude modulation (AM). In the first experiment, masked-threshold patterns were obtained for signal-modulation frequencies of 4, 16, 64 and 256 Hz in the presence of a half-octave-wide modulation masker, both applied to the same noise carrier with a bandwidth ranging from 1 to 4 kHz. In the seco...

To investigate short-distance, point-to-point, infrared channels, a test-bench and circuits were constructed to determine the limitations of existing optoelectronics. The results of these measurements are used to formulate a channel model which is employed for the subsequent analysis of candidate bandwidth efficient modulation schemes. A new multilevel modulation scheme,Adaptively Biased QAM (A...

A novel digital modulation scheme is proposed that allows to increase the data rate compared to uncoded modulation when the out-of-band power is fixed. If the data rate remains unchanged, this corresponds to a bandwidth reduction that is achieved by shaping the signal spectrum by the introduction of correlation in the transmitter. This correlation has to be resolved in the receiver by a maximum...

Abstract The cable industry is beginning to migrate to 100G core optical transport waves, which greatly improve fiber utilization while lowering transponder count for equivalent transport bandwidth. However, transporting 100G waves requires complex optical modulation to preserve performance and increase spectral efficiency. These modulation methods require several additional discrete optical co...

Multi4 phase-coded modulation (MHPM) is a bandwidth efficient modulation scheme which offers substantial coding gain over conventional digital modulations. In this paper, a new concept of MHPM with asymmetric modulation indices corresponding to the bipolar data + 1 and 1 is considered, and numerical results of the minimum Euclidean distances for such asymmetric binary multi-h schemes are provid...

Abstract—In wireless systems supporting slowly moving users, adaptive trellis-coded modulation (TCM) schemes have demonstrated large bandwidth efficiency gains over their nonadaptive counterparts. In systems with highly mobile users, the recently proposed adaptive bit-interleaved coded modulation (BICM) achieves a moderate bandwidth efficiency gain over previously proposed adaptive schemes and ...

The deep space optical communication is unguided optical communication without fiber, but is power and bandwidth limited. Technique used for communication in such a system is usually IM/DD and the choice of modulation is pulse position modulation since it is extremely power efficient, but it results in an exponential increase in required bandwidth. To overcome this limitation, multi-pulse PPM i...