Providing Real-Time Service in CDMA Wireless Networks

IET Communications, 2008

With much more advanced techniques employed, various applications can be supported by 3G CDMA-based wireless networks. Providing differentiated service over wireless networks has become a very important issue in the design of wireless networks. A new media access control protocol with a hierarchical scheduling algorithm to provide differentiated service for CDMA-based wireless networks is proposed. This protocol evolves from the distributed queuing random access protocol for CDMA wireless network. The proposed protocol has been designed to have an ability to accommodate integrated traffic in the networks with effective scheduling schemes. A series of simulation experiments have been carried out to evaluate the performance of the proposed protocol with the hierarchical scheduling algorithm. The results reveal that the proposed solution performs effectively in the integrated traffic composed of messages with or without time constraints and achieves proportional fairness among different types of traffic.

IEEE Transactions on Mobile Computing, 2004

In the third-generation (and beyond) wireless communication systems, there will be a mixture of different traffic classes, each having its own transmission rate characteristics and quality-of-service (QoS) requirements. In this paper, a QoS-oriented medium access control (MAC) protocol with fair packet loss sharing (FPLS) scheduling is proposed for wireless code-division multiple access (CDMA) communications. The QoS parameters under consideration are the transmission bit error rate (BER), packet loss, and delay requirements. The MAC protocol exploits both time-division and code-division statistical multiplexing. The BER requirements are guaranteed by properly arranging simultaneous packet transmissions and controlling their transmit power levels, whereas the packet loss and delay requirements are guaranteed by proper packet scheduling. The basic idea of FPLS is to schedule the transmission of multimedia packets in such a way that all the users have a fair share of packet loss according to their QoS requirements, which maximizes the number of the served users under the QoS constraints. Simulation results demonstrate effectiveness of the FPLS scheduler, in comparison with other previously proposed scheduling algorithms.

2007 IEEE 18th International Symposium on Personal, Indoor and Mobile Radio Communications, 2007

Wireless Local Area Networks (WLANs) are widely used in homes and offices, as well as in public places, mainly as the last mile of an Internet connection, but also as an interconnection between different devices. This extensive usage of WLANs, with the need of modern applications (such as Voice over IP) for high throughput and low transmission delays, impose the necessity for efficient protocols with Quality of Service (QoS) support. In previous work [6] the ability of Multi Carrier-Code Division Multiple Access (MC-CDMA) based Medium Access Control (MAC) protocols to achieve high efficiency has been demonstrated. This paper presents a MAC protocol, based on MC-CDMA that uses an Access Point (AP) to centrally control the network and provide QoS support. Extensive simulation results and a comparison with the standard IEEE 802.11e[3] prove the efficiency of the proposed protocol.

International Journal of Computer …, 2011

This article presents a survey on medium access control protocols for wireless multimedia networks. A basic overview of MAC protocol concepts is presented, and a framework is developed for comparisons. The MAC protocols covered in this article include Random Access protocols, Contention less protocols, TDMA CDMA, third-generation WCDMA schemes and Hybrid protocols proposed for wireless Multimedia Networks. The operation of each protocol is explained, and its advantages and disadvantages are presented. Finally, a qualitative comparative outline of the discussed protocols is provided.

Telecommunication Systems, 2013

This paper presents a new Time Division Multiple Access/Frequency Division Duplexing (TDMA/FDD) based Medium Access Control (MAC) protocol for broadband wireless networks, supporting Quality of Service (QoS) for real-time multimedia applications. It also gives the Call Blocking Probability (CBP), packet end-to-end delay and utilization analysis of different service classes, as they are most essential performance criterions in broadband wireless network assessment. The Connection Admission Control (CAC) mechanism in the proposed MAC efficiently organizes the bandwidth allocation for different service classes by means of a fairness based scheduling algorithm. In addition, the simulation model of the proposed MAC scheme is realized by using OPNET Modeler network simulator. The results of the analytical calculations for the CBPs are compared to those of the simulation of the proposed MAC, thus validity of the MAC protocol is proved.

Proceedings RAWCON 98. 1998 IEEE Radio and Wireless Conference (Cat. No.98EX194), 1998

A new analysis of throughput for a novel slotted CDMA-based medium-access-control protocol, with a channel4oad sensing feature, for wireless LANs is presented. Numerical results are shown of throughput versus oflered-load, and show that the proposed protocol oflers considerable throughput improvement when compared with ALOHA DS/SSMA ('random-access' CDMA).

IEEE INFOCOM 2007 - 26th IEEE International Conference on Computer Communications, 2007

Applying the code division multiple access (CDMA) techniques, we propose an efficient medium access control (MAC) protocol with single-transceiver for wireless ad hoc networks. Our protocol adopts the time-division method to solve the near-far power control problem inherently associated with the CDMAbased networks. In particular, employing the variable ad-hoc traffic indication messages (ATIM) window to properly determine the required transmission power for data packets, our scheme enables the interference-limited simultaneous transmissions to achieve the high utilization of the limited/precious bandwidth in wireless networks. In addition, our scheme requires only one transceiver per node, which reduces the hardware costs for large scale wireless networks. Using the Markov-chain techniques, we develop an analytical model to evaluate the aggregate throughput under our protocol. Both the analytical and simulation results show that our protocol can improve the network throughput significantly as compared with other existing schemes. Index Terms-Code division multiple access (CDMA), Markov chain, medium access control (MAC), near-far problem, wireless networks.

2011

When several independent terminals need to access a limited resource, a Medium Access Control (MAC) protocol is needed in order to manage and assign the resource. If no type of protocol is considered, conflicts could occur if more than one terminal wants to access the resource at the same time. Therefore, this work reports the analysis of MAC protocols. In addition to, we propose a protocol that handles transmission rates to maximize the transmission success rate. This proposed protocol is based on CSMA (Carrier Sense Multiple Access)-CDMA (Code Division Multiple Access). Simulations show that the protocol improves traffic transmission in the network, as compared with fixed rate mechanisms used to access the wireless medium.

International Journal of Business Data Communications and Networking, 2000

Computer Communications, 1997

In this paper, we study first the performance issues, especially message sojourn time and message overflow, of the TDMA protocol and then show how to use these results to design protocol parameters in order to meet the soft real-time requirements. We consider a single queue with multiple output (b messages) and finite buffer capacity (denoted by K), K and b being two protocol parameters that a designer can choose. Assuming Poisson fixed-length message arrivals, the exact expressions for the distribution function of the message sojourn time and the overflow probability are derived. It has been shown that these results can be applied to various particular cases (e.g. the infinite buffer capacity case) and therefore appear as a versatile solution for TDMA schemes. Moreover, the monotonicity for the overflow probability is proved, which gives us a theoretical base for the dimensioning task. Using the stated results, the design and implementation of real-time protocols based on TDMA can be achieved. An example is examined emphasizing the choice of the parameters K and b according to time and overflow constraints. ᭧ 1997 Elsevier Science B.V.