Types Of Communication Services Research Articles

A Dynamic Addressing Hybrid Routing Mechanism Based on Static Configuration in Urban Rail Transit Ad Hoc Network

With the rapid development of urban rail transit, the traditional urban rail wireless network based on fixed infrastructure is not in a position to meet the increasingly complex communication demand. At the same time, Ad Hoc network, as a special wireless mobile network, is developing rapidly. Applying this self-organized networking architecture to the urban rail vehicle–ground communication network can overcome the problems existing in the traditional urban rail communication system. The routing protocols that can achieve low delay and highly reliable data transmission are important in the urban rail transit scenario. Therefore, combined with the wireless Ad Hoc network and the characteristics of the urban rail transit scenario, this paper proposes a dynamic addressing hybrid routing mechanism based on static configuration. Using an improved AODV routing discovery algorithm and then writing the routing table into the router in advance for static configuration not only reduces network overhead but also prolongs the network’s lifetime. It also saves the delay of routing discovery. Then, the cluster head node dynamically monitors the link status, dynamically finds the path when the link needs to be replaced, and selects different update paths according to different types of communication services. Finally, each algorithm’s network performance parameters, like the routing discovery overhead, residual link lifetime, packet delivery rate, throughput, and end-to-end delay, are analyzed and compared.

OptIPuter: Enabling advanced applications with novel optical control planes and backplanes

Many emerging and anticipated advanced applications have demanding requirements that cannot be supported using traditional communication services, architecture, and technologies. Such requirements include those related to high performance, large scale data volume transport, dynamic provisioning, path flexibility, and stringent determinism for all service parameters. The OptIPuter research initiative was established to investigate the potential for meeting these and other exceptional challenges by creating new types of communication services that could be implemented as complements to traditional approaches and, in some special cases, as alternatives. In particular, the OptIPuter initiative has been exploring advanced communication services based on individually addressable, dynamically allocated lightpaths. These approaches require novel control plane and backplane architecture and technology. As part of its core research agenda, the OptIPuter initiative designed and deployed such architecture and technology, which is described here along with a large scale testbed implementation, including national and international extensions. This testbed was used for a series of experiments, and the results are summarized.

Design of strict optical orthogonal codes with nonconstant weights for use in optical code-division multiplexing multimedia systems

We report the design of a new family of strict optical orthogonal codes (SOOCs) that permit the use of nonconstant code weights in optical code-division multiplexing (OCDM) systems. Because this new code can possess any number of pulses (i.e., 1s) in each codeword while still maintaining the minimum autocorrelation and cross-correlation constraints (i.e., “1”) for incoherent optical processing, its use can flexibly support multimedia applications in an OCDM system to meet varieties of transmission performance and traffic requirements which are demanded by different types of communication services. The method of designing the proposed codes is presented, and the bound on code length is also given.

Digital two-level PAM and analogue PWM hybrid optical fiber transmission systems for TV and data applications

We propose a novel optical fiber transmission system for supporting both digital and analogue communications in a very cost-effective fashion. The proposed system simultaneously uses a 2-level pulse amplitude modulation (PAM) for data communications and an analogue pulse width modulation (PWM) for TV applications. The principle of the 2-level PAM and analogue PWM hybrid scheme is presented, and its some distinguishing features are explained. Moreover, this proposed technique requires the same transmission bandwidth as a conventional analogue PWM scheme. Consequently, two different types of communication services can be transmitted over a common optical fiber channel by using the 2-level PAM and analogue PWM technique, without the use of wavelength- or frequency- or time-division multiplexing.