Time Division Basis Research Articles

An Automatic Neutral Section Power Supplier Serving as Railway Power Conditioner on Time-Division Basis

An Automatic Neutral Section Power Supplier Serving as Railway Power Conditioner on Time-Division Basis

On Spatial Domain Cognitive Radio Using Single-Radio Parasitic Antenna Arrays

Spectrum sensing for cognitive radio is studied, using an electronically steerable parasitic antenna receptor (ESPAR), which relies on a single RF front end, and therefore meets the demanding low cost, power and size requirements of modern wireless terminals. We develop a strategy whereby the angular domain is divided into sectors, that are accessed via beamforming on a time division basis, to detect signals from primary users. We study the performance of detection metrics based on energy received per beam, and also eigenvalue-based detection statistics through considering the covariance matrix across the various directional beams. The ESPAR is able to achieve over 6dBi SNR improvement due to its beamforming capability. Further, once primary users' signals have been detected, directional transmit opportunities which do not interfere with active PUs become available, and we develop an adaptive beamforming algorithm to capitalise on these to efficiently utilise the spatial domain, which numerically optimises the beampattern and antenna efficiency using a convex formulation. The resulting beampatterns give between -20dB and -30dB nulls in the primary user direction.

Rural Load Management using Information Technology

The mismatch between the generation and demand for electrical power is increasing at an alarming rate. This is mainly due shortage of conventional resources, use of appropriate technology for alternate energy sources and lack of awareness about energy conservation. Power supply to domestic, commercial and industrial consumers is a difficult task to the utilities controlled by the government. In rural India, irrigation pump sets are the major loads. The technical aptitude, attitude and co operation of the consumers helps a lot in energy management. The strategic power supply is affected if the consumers are not complying with the norms. A strategy is framed to provide power to domestic appliances around the clock and agricultural consumers on time division basis. But the local technicians play a corruptive role to violate this which is leading to overloading/failure of the distribution transformers frequently. Here, an attempt is made to devise a method to overcome the problem of agricultural consumers who are getting power on time division basis. A control unit is installed at each distribution station to automatically monitor and control the power supply to domestic and agricultural consumers as per the pre defined schedule. This paper explains the use of electronics and information technology in rural areas for better management of the power supply and consumption. The unauthorized connection leading to failure of distribution transformers is also taken care.

Rural Load Management using Information Technology

The mismatch between the generation and demand for electrical power is increasing at an alarming rate. This is mainly due shortage of conventional resources, use of appropriate technology for alternate energy sources and lack of awareness about energy conservation. Power supply to domestic, commercial and industrial consumers is a difficult task to the utilities controlled by the government. In rural India, irrigation pump sets are the major loads. The technical aptitude, attitude and co operation of the consumers helps a lot in energy management. The strategic power supply is affected if the consumers are not complying with the norms. A strategy is framed to provide power to domestic appliances around the clock and agricultural consumers on time division basis. But the local technicians play a corruptive role to violate this which is leading to overloading/failure of the distribution transformers frequently. Here, an attempt is made to devise a method to overcome the problem of agricultural consumers who are getting power on time division basis. A control unit is installed at each distribution station to automatically monitor and control the power supply to domestic and agricultural consumers as per the pre defined schedule. This paper explains the use of electronics and information technology in rural areas for better management of the power supply and consumption. The unauthorized connection leading to failure of distribution transformers is also taken care.

Joint scheduling and power control for multicasting in cellular wireless networks

We consider a cellular wireless network. Our aim is to develop adaptive-power scheduling algorithms that enable area base stations to coordinate, on a time-division basis, the transmission of multicast packets to identified client nodes, for scenarios under which a prescribed code rate is employed. Such mechanisms can be implemented by 4G long term evolution (LTE) systems using multimedia broadcast multicast services (MBMS), meshed WiFi networks, or mobile backbone based ad hoc wireless networks. We show that the joint scheduling and power control problem can be represented as a mixed-integer linear programming model, which is NP-hard. Consequently, we present three heuristic algorithms of polynomial complexity for solving the problem in a practical manner. For small network layouts, our centralized heuristic algorithm is shown to achieve a throughput rate performance that is close to that attained by the optimal scheme. All three of our heuristic algorithms are shown to yield excellent throughput rate performance behavior. The use of power adaptations, when compared with fixed transmit power operations, leads to enhanced throughput rate performance while also lowering communications energy consumption levels. Comparisons with LTE MBMS over single frequency network based schemes have shown our algorithms to offer enhanced spectral efficiency performance, while providing high client coverage.

Infinite-length pilot aided equalization

A single carrier pilot-assisted transmission scheme is considered in this letter. Specifically, we focus on the case of synchronous transmission where one pilot symbol is periodically inserted in the transmitted sequence on a time-division multiplexing basis. A new equalization scheme, where the knowledge of pilot symbols is exploited by the equalizer to generate an estimate of the noise affecting the symbol to be detected, is introduced and analyzed. The criterion used to compute the equalizer coefficients is the minimization of the mean-square error (MSE). The main result of our analysis is that the optimal pilot aided equalizer (PAE) can be decomposed as the cascade of a minimum MSE (MMSE) linear equalizer (LE) and a data-aided noise estimation filter. This result completes and extends the noise-predictive view of decision feedback equalization to general data-aided equalization. The performance of the proposed PAE is compared to that of theMMSE-LE and that of theMMSE decision feedback equalizer both for static and for fading channels.

The rate region of a cooperative scheduling system

A wireless communication system where a common base station is scheduled to transmit information to multiple mobile users on a time division (TD) basis is considered. The capacity region of this system is found for the two user case and the optimal scheduling scheme is proposed which achieves the boundary of the capacity region. Furthermore, the optimal scheduling scheme is found for the case when the remote mobile users can perform downlink cooperation and the achievable rate region of the downlink cooperative system is characterized. Finally, a simple iterative algorithm is proposed for finding the resource allocation parameters and the scheduling scheme for the cooperative system.

The effective capacity of a time division downlink scheduling system

A wireless communication system where a common base station (BS) is scheduled to transmit information to mobile users on a time division (TD) basis, under quality of service (QoS) constraints is considered. The quality of service requirement is specified in terms of the asymptotic decay rate of the buffer occupancy. The effective capacity of this system is characterized and the optimal scheduling scheme which achieves the boundary of the effective capacity region is found. It is further shown that the optimal scheduling scheme without quality of service constraints and the opportunistic scheduling schemes fall out as special cases of a more generalized class of scheduling schemes derived in this paper.

Electronic musical instrument with automatic performing function

Melody and chord tone data are read out from a melody RAM and a chord RAM under the control of address counters in a CPU, and are supplied to LSIs. The LSIs are controlled by the CPU for operation on a time division basis for a plurality of channels, so that a given melody and chord are simultaneously produced from a loudspeaker.

Electronic musical instrument by time division multiplexed tone selection

An electronic musical instrument comprises a plurality of key switches and a key switch scanning circuit for sequentially scanning said key switches at a predetermined speed to produce time division multiplexed key data signals representing the depressed states of respective keys. The instrument further comprises a time division multiplexed tone waveform generating circuit which generates tone signals on a time division basis and in synchronism with the scanning of said key switches, said tone signals consisting of waveform samples of all the notes, i.e. tone frequencies, that the instrument can generate, and means which delivers out the output signal from the time division multiplexed tone waveform generating circuit at the moments when said time division multiplexed key data signals arrive, thereby producing plurality of tone signals in a time division multiplexed manner.

System MCET-1 An Experimental Microprocessor-Controlled Electronic Telex

System MCET-1, an experimental Microprocessor-Controlled Electronic Telex for 200 lines/trunks, has been described. Scanning, decadic out pulsing and character transfer are done by autonomous units. Character transfer takes place on a time-division basis through the ‘Character Transfer Highway’ connecting all terminations which are treated as memory- mapped input-output ports of microprocessor for transmission of signals. All operational programs, except ‘Scanner Program’, are executed in the base level. Scanner Program, called under interrupt from ‘Autonomous Scanning Unit’, allots a Call Control Register (CCR) for each new call and enters the scan data into relevant CCRs. Executive Control Program periodically monitors the status of CCRs and schedules the programs.The system has greatly simplified operational software and can accommodate an elaborate maintenance and diagnostic software.

An experimental electronic telephone exchange on a time-division basis

The paper describes an electronic telephone exchange based on time-division techniques but using a common pulse supply circuit for its controls and speech-path carrier pulses. A ‘semi-highway’ switching system is used. Each subscriber is allotted a fixed pulse of a train of pulses. Connections between a calling and called subscriber are made either by shifting the phase of the pulse at the outgoing side of connection or by the use of audio links. Since the control and memory circuits are connected at the outgoing side of the system the number of them is reduced and concentrated. An outline of the system is given and its control circuits, switching network and set-up procedure are briefly explained. The traffic-handling behaviour of system is considered and the method of determining the number of channels in a highway is indicated.The first model based on these principles was built by the authors in March, 1958. It was on a smaller scale than the model described, which was completed in March, 1960, and is at present under test.