Duty-cycle division multiplexing (DCDM): a novel and economical optical multiplexing and electrical demultiplexing technique for high speed fiber optics networks

A new multiplexing and demultiplexing technique based on duty cycle division is proposed, thus the name duty cycle division multiplexing (DCDM). DCDM can be applied in both electrical and optical domains. The new technique allows for more efficient use of time slots as well as the spectrum, taking advantage of both the conventional TDM and FDM. In this paper, three channels operating at the same speed of 10 Gbps are multiplexed in the optical domain and demultiplexed in the electrical domain. The performance comparison is made against 30 Gbps TDM, and the experimental simulation results show that the minimum sensitivity achieved is -26 dBm and -25.5 dBm for the two systems respectively, thus a 0.5 dB improvement

Duty Cycle Division Multiplexing (DCDM): a new electrical multiplexing technique for high speed optical communication systems

A new multiplexing technique based on duty cycle division is proposed, thus the name duty cycle division multiplexing (DCDM). DCDM can be applied in both electrical and optical domains, for wired and wireless systems. The new technique allows for more efficient use of time slots as well as the spectrum, taking advantage of both the conventional TDM and FDM. In this paper, three channels operating at the same speed of 10 Gbps per channel are multiplexed in the electrical domain. The performance comparison is made against 3times10 Gbps TDM, and the experimental simulation results show that the DCDM system can support higher bit rate than TDM and also, it is less sensitive to the chromatic dispersion effect

The Future Electrical Multiplexing Technique for High Speed Optical Fibre

Advancement in transmission technology based on fiber optic such as multiplexing technique is an attractive research area for future development of high capacity and high speed optical communication system. Typical electrical based multiplexing such as electrical time division multiplexing (ETDM) and duty cycle division multiplexing (DCDM) have difficulty to fulfil the requirements of modern fiber optic communication with practical solution. Multi slot amplitude coding (MSAC) is the latest multiplexing technique that has been proposed as an alternative to ETDM and DCDM. The results show that the spectral width is reduced by around 25%, not less than 55% improvement of chromatic dispersion (CD) tolerance, 0.6 dB better receiver sensitivity, and 1.5 dB better optical signal to noise ratio (OSNR) compared to DCDM for 30 Gbit/s transmission capacity. The spectral width for 3 × 10 Gbit/s, 4 × 10 Gbit/s and 5 × 10 Gbit/s MSAC is 60 GHz, which indicates improvement of spectral efficiency. This advantage is not possible to be achieved through ETDM technique. In addition, 10 GHz clock signal can be extracted from the MSAC signal which is important for recovery circuit at receiver since it is similar to symbol rate

Absolute polar duty cycle division multiplexing: an economical and spectral efficient multiplexing technique

A new multiplexing technique based on duty cycle division is proposed, under the name: absolute polar duty cycle division multiplexing (APDCDM). The new technique allows for more efficient use of time slots as well as the spectrum, taking the advantage of both the conventional TDM and FDM. The basic properties based on theoretical analysis as well as simulation studies have been done to evaluate the performance of this technique based on the signal energy and symbol error rate (SER). In this paper the performance of absolute polar duty cycle division multiplexing is compared with multilevel M-ary as well as with the time division multiplexing (TDM) techniques. The simulation has been set for wireless transmission based on free space propagation model with adaptive white Gaussian noise (AWGN). PSK and QAM are used as modulation schemes to evaluate these techniques against data rates and number of users. The study shows that by increasing the number of users, the energy per bit in APDCDM has better performance than that of TDM technique. The simulation result correspond with the theoretical study shows that absolute polar duty cycle division multiplexing (APDCDM), has better SER than TDM

Absolute polar duty cycle division multiplexing: an economical and spectral efficient multiplexing technique

A new multiplexing technique based on duty cycle division is proposed, under the name: Absolute Polar Duty Cycle Division Multiplexing (APDCDM). The new technique allows for more efficient use of time slots as well as the spectrum, taking the advantage of both the conventional TDM and FDM. The basic properties based on theoretical analysis as well as simulation studies have been done to evaluate the performance of this technique based on the signal energy and symbol error rate (SER). In this paper the performance of Absolute Polar Duty Cycle Division Multiplexing is compared with multilevel M-ary as well as with the time division multiplexing (TDM) techniques. The simulation has been set for wireless transmission based on free space propagation model with adaptive white Gaussian noise (AWGN). PSK and QAM are used as modulation schemes to evaluate these techniques against data rates and number of users. The study shows that by increasing the number of users, the energy per bit in APDCDM has better performance than that of TDM technique. The simulation result correspond with the theoretical study shows that Absolute Polar Duty Cycle Division Multiplexing (APDCDM), has better SER than TDM

Space-Time-Frequency Diversity for OFDM-Based Indoor Power Line Communication

In this paper, full rate space-time-frequency coding applied to orthogonal frequency division multiplexing based power line communication systems. The proposed systems yield both time and frequency diversity and keep transmission rate full. Performances of the systems are evaluated for three conductors of low voltage indoor cables and are compared with space-frequency and space-time-frequency coding applied power line communication systems in the literature. Owing to the higher order diversity level the proposed full rate space-time-frequency systems have an increasing advantage over space-frequency systems as the SNR level above 12.5dB. On the other hand owing to transmission rate advantage the proposed full rate space-time-frequency systems can have more than 6dB gain over the other space-time-frequency coding applied power line communication systems in the literature

Low-Complexity Iterative Detection for Orthogonal Time Frequency Space Modulation

We elaborate on the recently proposed orthogonal time frequency space (OTFS) modulation technique, which provides significant advantages over orthogonal frequency division multiplexing (OFDM) in Doppler channels. We first derive the input--output relation describing OTFS modulation and demodulation (mod/demod) for delay--Doppler channels with arbitrary number of paths, with given delay and Doppler values. We then propose a low-complexity message passing (MP) detection algorithm, which is suitable for large-scale OTFS taking advantage of the inherent channel sparsity. Since the fractional Doppler paths (i.e., not exactly aligned with the Doppler taps) produce the inter Doppler interference (IDI), we adapt the MP detection algorithm to compensate for the effect of IDI in order to further improve performance. Simulations results illustrate the superior performance gains of OTFS over OFDM under various channel conditions.Comment: 6 pages, 7 figure

Adaptive and Robust Channel Estimation for Pilot-aided OFDM Systems

A time domain interpolation method is presented and applied to channel estimation for pilot-aided Orthogonal Frequency Division Multiplexing (OFDM) system. One key advantage of this method is that it dynamically selects suitable basis functions to approximate the channel transfer function by studying the shape of its Inverse Fourier transform. Which results in a very good approximation by using as few as possible basis functions, and provides significant reduction of additive white Gaussian noise (AWGN) and Inter Carrier Interference (ICI) at the same time. Theoretical analysis and simulations show that it is an efficient method for approximating various kinds of OFDM channels