Adaptive Throughput Optimization in Downlink Wireless OFDM System

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This paper presents a scheduling scheme for packet transmission in OFDM wireless system with adaptive techniques.The concept of efficient transmission capacity is introduced to make scheduling decisions based on channel conditions.We present a mathematical technique for determining the optimum transmission rate, packet size, Forward Error Correction and constellation size in wireless system that have multi-carriers for OFDM modulation in downlink transmission. The throughput is defined as the number of bits per second correctly received. Trade-offs between the throughput and the operation range are observed, and equations are derived for the optimal choice of the design variables. These parameters are SNR dependent and can be adapted dynamically in response to the mobility of a wireless data terminal. We also look at the joint optimization problem involving all the design parameters together. In the low SNR region it is achieved by adapting the symbol rate so that the received SNR per symbol stays at some preferred value. Finally, we give a characterization of the optimal parameter values as functions of received SNR Simulation results are given to demonstrate efficiency of the scheme.

Cite this paper

FAKHRI, Y. , NSIRI, B. , ABOUTAJDINE, D. and VIDAL, J. (2008) Adaptive Throughput Optimization in Downlink Wireless OFDM System. Int’l J. of Communications, Network and System Sciences, 1, 10-15. doi: 10.4236/ijcns.2008.11002.

References

[1] H. Sampath, S. Talwar, J. Tellado, V. Erceg, and A.Paulraj, A Fourthgeneration MIMO-OFDM Broadband Wireless System: Design, Performance,and Field Trial Results, IEEE Communications Magazine, vol. 40, no. 9, pp. 143-149, 2002
[2] T.S. Rappaport, A. Annamalai, R. M. Buehrer, and W. H. Tranter,Wireless Communications: Past Events and a Future Perspective, IEEE Communications Magazine, pp. 148-161, May 2002
[3] T.S. Rappaport, A. Annamalai, R. M. Buehrer, and W. H. Tranter,Wireless Communications: Past Events and a Future Perspective, IEEE Communications Magazine, pp. 148-161, May 2002
[4] J. A. C. Bingham, Multicarrier Modulation for Data Transmisson: an Idea whose Time Has Come, IEEE Communications Magazine, vol. 28, no. 5, pp. 5-14,May 1990
[5] Y.Fakhri,D.Aboutajdine,J.Vidal. Multicarrier power allocation for maximum throughput in delayed channel knowledge conditions. Proc. Of International Workshop on Wireless Communication in Underground and Confined Areas IWWCUCA2005, Val-dor, Quebec, Canada, Juin 6-7, 2005
[6] J. Goldsmith and S.-G. Chua, Adaptive coded modulation for fading channels, IEEE Trans.Commun., vol. 46, pp. 595-602, May 1998
[7] H. Matsuoka, S. Sampei, N. Morinaga, and Y. Kamio, Adaptive modulation system with variable coding rate concatenated code for high quality multi-media communication systems, IEICE Trans. Commun., vol. E79-B, pp. 328-334, Mar. 1996.
[8] M. B. Pursley and J. M. Shea, Adaptive non uniform phase-shift-key modulation for multimedia traffic in wireless networks, IEEE J. Select. Areas Commun, vol. 18, pp. 1394-1407, Aug. 2000.
[9] S. Catreux, P. F. Driessen, and L. J. Greenstein, Data throughputs using multiple-input multiple-output (MIMO) techniques in a noiselimited cellular environment, IEEE Trans. Wireless Commun., vol. 1, pp. 226-235, Apr. 2002.
[10] J. G. Proakis, Digital Communications, 4th Ed, New York: McGraw-Hill, 2000.
[11] S. T. Chung, A. Goldsmith, Degrees of freedom in adaptive modulation:a unified view, IEEE Trans. Commun., vol. 49, pp. 1561-1571, Sep. 2001.
[12] Clark,George C., Jr., Cain, J. Bibb, Error-Correction Coding for Digital Communications. Plenum Press, NY, 1981. p38.
[13] Clark,George C., Jr., Cain, J. Bibb, Error-Correction Coding for Digital Communications. Plenum Press, NY, 1981. p219.                                                                                                                            eww150205lx
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Implementation and Evaluation of Transport Layer Protocol Executing Error Correction (ECP)

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http://www.scirp.org/journal/PaperInformation.aspx?PaperID=48728#.VKNvE8nQrzE

ABSTRACT

Technologies for retransmission control and error correction are available for communications over the Internet to improve reliability of data. For communications that require the data reliability be ensured, TCP, which performs retransmission control, is often employed. However, for environments and services where response confirmation and retransmission are difficult, error correction technologies are employed. Error correction is generally implemented on UDP, but the existing framework implemented on UDP frequently does not consider the maximum frame size of the data link layer and relegates data division to the IP module. The IP module divides data according to the maximum size for the data link, and the receiving IP module reconstructs the divided data. For a data link layer typified by the current Ethernet with an error detection function, the frame is often destroyed upon error detection. At the IP module, the specification allows destruction of the entire dataset whenever divided data necessary for reconstruction is incomplete. Consequently, an error in a single bit results in a total loss of data handed to the IP module, and thus error correction performance declines with the increase in data size handed to the IP module. The present study considers the MTU of the data link layer and proposes error correction protocol (ECP) over IP, which decreases the transfer data volume flowing to the data link layer by dividing data into blocks of appropriate size based on designated error correction code and its parameters (thus improving error correction performance) and assesses the performance of ECP. Experimental results demonstrate that performance is comparable or better than existing error correction frameworks. Results also show that when a specification not ensuring the reliability of the data link layer was employed, error correction was superior to existing frameworks on UDP.

Cite this paper

Matsuzawa, T. and Shimazu, K. (2014) Implementation and Evaluation of Transport Layer Protocol Executing Error Correction (ECP). Communications and Network, 6, 175-185. doi: 10.4236/cn.2014.63019.

References

[1] Watson, M., Began, A. and Roca, V. (2011) Forward Error Correction (FEC) Framework. Request for Comments, 6363 (Internet Engineering Task Force).
[2] Alteon Networks Extended Frame Sizes for Next Generation Ethernets, a White Paper.
http://staff.psc.edu/mathis/MTU/AlteonExtendedFrames_W0601.pdf
[3] Reed, I.S. and Solomon, G. (1960) Polynomial Codes over Certain Finite Fields. J.SIAM, 8, 300-304. http://dx.doi.org/10.1137/0108018
[4] Gallager, R.G. (1962) Low-Density Parity-Check Codes. MIT Press, Cambridge. (Preliminary Version in IRE Trans on Inf. Theory, 8, 21-28.)
[5] Bose, R.C. and Ray-Chaudhuri, D.K. (1960) On a Class of Error-Correcting Binary Group Codes. Inform. Control, 3, 68-79. http://dx.doi.org/10.1016/S0019-9958(60)90287-4
[6] Hocquenghem, A. (1959) Codes correcteursd’erreurs. Chiffres, 2, 147-156.
[7] Begen, A. (2011) Session Description Protocol Elements for the Forward Error Correction (FEC) Framework. Request for Comments, 6364 (Internet Engineering Task Force).
[8] Deering, S. and Hinden, R. (1998) Internet Protocol, Version 6 (IPv6) Specification. Request for Comments, 2460 (Internet Engineering Task Force).
[9] IEEE 802.3-2002 (1985) IEEE Standard for Information Technology, Telecommunications and Information Exchange between Systems, Local and Metropolitan Area Networks, Specific Requireme-
nts Part: 3 Carrier Sense Multiple Access with Collision Detection (CSMA/CD) Access Method and Physical Layer Specifications Low-Density Parity-Check Codes.
[10] Lacan, J., Roca, V., Peltotalo, J. and Peltotalo, S. (2009) Reed-Solomon Forward Error Correction (FEC) Scheme. Request for Comments, 5510 (Internet Engineering Task Force).
[11] McCann, J., Deering, S. and Mogul, J. (1996) Path MTU Discovery for IP Version 6. Request for Comments, 1981 (Internet Engineering Task Force).                                                                                       eww141231lx
[12] Roca, V., Cunche, M., Lacan, J., Bouabdallah, A. and Matsuzono, K. (2013) Simple Reed-Solomon Forward Error Correction (FEC) Scheme for FECFRAME. Request for Comments, 6865 (Internet Engineering Task Force).
[13] IEEE 802.2. (1998) IEEE Standard for Information Technology, Telecommunications and Information Exchange between Systems, Local and Metropolitan Area Networks, Specific Requirements Part 2: Logical Link Control.