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Issue No.09 - September (2009 vol.8)
pp: 1265-1279
Sangho Shin , Columbia University, New York
Henning Schulzrinne , Columbia University, New York
ABSTRACT
We measured the capacity for VoIP traffic in an IEEE 802.11b wireless testbed and compared it with the theoretical capacity and our simulation results. We identified factors that have been commonly overlooked in past studies but affect experiments and simulations. We found that in many papers, the capacity for VoIP traffic has been measured via simulations or experiments without considering these factors, showing different capacity in each paper. After these corrections, simulations and experiments yielded a capacity estimate of 15 calls for 64 kb/s CBR VoIP traffic with 20 ms packetization interval and 38 calls for VBR VoIP traffic with a 0.39 activity ratio. Furthermore, we measured the capacity for VoIP traffic using each access category introduced in the 802.11e standard and the effect of the TCP traffic on VoIP traffic. We found that while the 802.11e standard can protect the QoS of VoIP against TCP traffic, it does not improve the capacity due to the significant retransmissions during TXOP.
INDEX TERMS
VoIP, capacity, 802.11, MAC layer, wireless network.
CITATION
Sangho Shin, Henning Schulzrinne, "Measurement and Analysis of the VoIP Capacity in IEEE 802.11 WLAN", IEEE Transactions on Mobile Computing, vol.8, no. 9, pp. 1265-1279, September 2009, doi:10.1109/TMC.2009.49
REFERENCES
[1] D.P. Hole and F.A. Tobagi, “Capacity of an IEEE 802.11b Wireless LAN Supporting VoIP,” Proc. IEEE Int'l Conf. Comm. (ICC '04), pp.196-201, 2004.
[2] M. Veeraraghavan, N. Cocker, and T. Moors, “Support of Voice Services in IEEE 802.11 Wireless LANs,” Proc. IEEE INFOCOM, vol. 1, pp. 488-497, 2001.
[3] D. Chen, S. Garg, M. Kappes, and K.S. Trivedi, “Supporting VoIP Traffic in IEEE 802.11 WLAN with Enhanced Medium Access Control (MAC) for Quality of Service,” technical report, Avaya Labs Research, 2002.
[4] S. Garg and M. Kappes, “An Experimental Study of Throughput for UDP and VoIP Traffic in IEEE 802.11b Networks,” Proc. IEEE Wireless Comm. and Networking Conf. (WCNC '03), vol. 3, pp. 1748-1753, 2003.
[5] T. Kodama and Y. Katsube, “Voice Performance in WLAN Networks—An Experimental Study,” Proc. Global Telecomm. Conf. (GLOBECOM '03), pp. 3504-3508, 2003.
[6] K. Medepalli, P. Gopalakrishnan, D. Famolari, and T. Kodama, “Voice Capacity of IEEE 802.11b, 802.11a and 802.11g Wireless LANs,” Proc. Global Telecomm. Conf. (GLOBECOM '04), Nov. 2004.
[7] N.T. Dao, X. Wei, and R.A. Malaney, “The Voice Capacity of WiFi for Best Effort and Prioritized Traffic,” Proc. Auswireless Conf., Aug. 2006.
[8] T.J. Patel, V.A. Ogale, N.C.S. Baek, and R. Parkm, “Channel Capacity Estimation in VOIP Channels over Wireless Networks,” http://users.ece.utexas.edu/wireless/EE381K11_Spring03/ projects11.1.pdf, 2003.
[9] F. Anjum, M. Elaoud, D. Famolari, A. Ghosh, R. Vaidyanathan, A. Dutta, and P. Agrawa, “Voice Performance in WLAN Networks. An Experimental Study,” Proc. Global Telecomm. Conf. (GLOBECOM '03), Dec. 2003.
[10] A. Lakas and M. Boulmalf, “Experimental Analysis of VoIP over Wireless Local Area Networks,” J. Comm., vol. 2, pp. 3-9, June 2007.
[11] I. Dangerfield, D. Malone, and D.J. Leith, “Experimental Evaluation of 802.11e EDCA for Enhanced Voice over WLAN Performance,” Proc. Int'l Symp. Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks (WiOpt '06), Apr. 2006.
[12] P. Brady, “A Model for Generating On-Off Speech Patterns in Two-Way Conversation,” Bell Systems Technical J., vol. 48, no. 7, pp.2245-2272, Sept. 1969.
[13] IEEE Std. 802.11e, Wireless LAN Medium Access Control (MAC) and Physical (PHY) Specifications: Medium Access Control (MAC) Quality of Service Enhancements, IEEE, Nov. 2005.
[14] L. Cai, X.S. Shen, J.W. Mark, L. Cai, and Y. Xiao, “Voice Capacity Analysis of WLAN with Unbalanced Traffic,” Proc. Int'l Conf. Quality of Service in Heterogeneous Wired/Wireless Networks (QSHINE '05), Aug. 2005.
[15] A. Trad, F. Munir, and H. Afifi, “Capacity Evaluation of VoIP in IEEE 802.11e WLAN Environment,” Proc. IEEE Consumer Comm. and Networking Conf. (CCNC '05), Jan. 2005.
[16] N. Hegde, A. Proutiere, and J. Roberts, “Evaluating the Voice Capacity of 802.11 WLAN under Distributed Control,” Proc. IEEE Workshop Local and Metropolitan Area Networks (LANMAN '05), Sept. 2005.
[17] S. Harsha, A. Kumar, and V. Sharma, “An Analytical Model for the Capacity Estimation of Combined VoIP and TCP File Transfers over EDCA in an IEEE 802.11e WLAN,” Proc. IEEE Int'l Workshop Quality of Service (IWQoS '06), June 2006.
[18] T. Kawata, S. Shin, A.G. Forte, and H. Schulzrinne, “Using Dynamic PCF to Improve the Capacity for VoIP Traffic in IEEE 802.11 Networks,” Proc. IEEE Wireless Comm. and Networking Conf. (WCNC '05), vol. 3, pp. 13-17, Mar. 2005.
[19] W. Wang, S.C. Liew, and V. Li, “Solutions to Performance Problems in VoIP over a 802.11 Wireless LAN,” IEEE Trans. Vehicular Technology, vol. 54, no. 1, pp. 366-384, Jan. 2005.
[20] S. Shin and H. Schulzrinne, “Balancing Uplink and Downlink Delay of VoIP Traffic in IEEE 802.11 WLANs Using APC,” Proc. Int'l Conf. Quality of Service in Heterogeneous Wired/Wireless Networks (QSHINE '06), Aug. 2006.
[21] T. Li and D. Logothetis, “Analysis of a Polling System for Telephony Traffic with Application to Wireless LANs,” IEEE Trans. Wireless Comm., vol. 5, no. 6, pp. 1284-1293, June 2006.
[22] S. McCanne and S. Floyd, ns Network Simulator, http://www.isi.edu/nsnamns/, 2009.
[23] QualNet Network Simulator 3.7, http:/www.scalable-networks. com, 2009.
[24] D. Raychaudhuri, I. Seskar, M. Ott, S. Ganu, K., Ramachandran, H. Kremo, R. Siracusa, H. Liu, and M. Singh, “Overview of the ORBIT Radio Grid Testbed for Evaluation of Next-generation Wireless Network Protocols,” Proc. IEEE Wireless Comm. and Networking Conf. (WCNC '05), pp. 1664-1669, 2005.
[25] IEEE Std. 802.11, Wireless LAN Medium Access Control (MAC) and Physical (PHY) Specifications: Higher-Speed Physical Layer Extension in the 2.4 GHz Band, IEEE, 1999.
[26] Artificial Conversational Speech, ITU-T Recommendation, p. 59, 1993.
[27] QualNet 3.7 User's Guide. Scalable Network Technologies, Inc., 2005.
[28] S. Wanstedt, M. Ericson, L. Hevizi, J. Pettersson, and J. Barta, “The Effect of F-DPCH on VoIP over HSDPA Capacity,” Proc. IEEE Vehicular Technology Conf., pp. 410-414, May 2006.
[29] M. Benveniste and Z. Tao, “Performance Evaluation of a Medium Access Control Protocol for IEEE 802.11s Mesh Networks,” Proc. IEEE Sarnoff Symp., Apr. 2006.
[30] K. Yasukawa, A.G. Forte, and H. Schulzrinne, “Distributed Delay Estimation and Call Admission Control in IEEE 802.11 WLANs,” Proc. IEEE Int'l Conf. Network Protocols (ICNP '07), Oct. 2007.
[31] One-Way Transmission Time, ITU-T G.114, 2003.
[32] CISCO, Understanding Delay in Packet Voice Networks, http://www.cisco.com/application/pdf/paws/ 5125delay-details.pdf, 2009.
[33] The E-model, a Computational Model for Use in Transmission Planning, ITU-T Recommendation G.107, Mar. 2003.
[34] S.M.J. Fitzpatrick and J. Murphy, “SCTP Based Handover Mechanism for VoIP over IEEE 802.11b Wireless LAN with Heterogeneous Transmission Rates,” Proc. IEEE Int'l Conf. Comm. (ICC '06), June 2006.
[35] L. Carvalho, E. Mota, R. Aguiar, A.F. Lima, and J.N. de Souza, “An E-Model Implementation for Speech Quality Evaluation in VoIP Systems,” Proc. IEEE Symp. Computers and Comm. (ISCC '05), June 2005.
[36] A. Passito, E. Mota, R. Aguiar, L. Carvalho, E. Moura, A. Briglia, and I. Biris, “Using an E-Model Implementation to Evaluate Speech Quality in Voice over 802.11b Networks with VPN/IPSec,” Proc. Wireless Comm., Networking, and Mobile Computing (WiMob '05), Aug. 2005.
[37] M. Narbutt and M. Davis, “Gauging VoIP Call Quality from 802.11 WLAN Resource Usage,” Proc. World of Wireless, Mobile, and Multimedia Networks (WoWMoM '06), June 2006.
[38] M. Rodrig, C. Reis, R. Mahajan, D. Wetherall, and J. Zahorjan, “Measurement-Based Characterization of 802.11 in a Hotspot Setting,” Proc. ACM SIGCOMM W-WIND Workshop, pp. 5-10, Aug. 2005.
[39] M. Lacage, M.H. Manshaei, and T. Turletti, “IEEE 802.11 Rate Adaptation: A Practical Approach,” Proc. Int'l Symp. Modeling Analysis and Simulation of Wireless and Mobile Systems (MSWiM '04), pp. 126-134, 2004.
[40] H. Kremo, I. Seskar, and P. Spasojevic, “An ORBIT Testbed Study of 802.11b DCF: Throughput, Latency, and the Capture Effect,” Proc. IEEE Int'l Conf. Testbeds and Research Infrastructures for the Development of Networks and Communities (Tridentcom '06), pp. 308-309, Mar. 2006.
[41] Wireless LAN Medium Access Control (MAC) and Physical (PHY) Specifications, IEEE, 1999.
[42] H. Velayos and G. Karlsson, “Techniques to Reduce IEEE 802.11b MAC Layer Handover Time,” technical report, Royal Inst. of Tech nology, Apr. 2003.
[43] TTCP Utility, http://www.pcausa.com/Utilitiespcattcp.htm , 2009.
[44] IEEE Std. 802.11, Wireless LAN Medium Access Control (MAC) and Physical (PHY) Specifications: Further Higher Data Rate Extension in the 2.4 GHz Band, IEEE, 2003.
[45] J. Lv, X. Zhang, and X. Han, “Performance Analysis for IEEE 802.11e EDCF Service Differentiation,” Proc. Fourth Int'l Conf. Networked Computing and Advanced Information Management, Sept. 2008.
[46] H. Zhu and I. Chlamtac, “Performance Analysis for IEEE 802.11e EDCF Service Differentiation,” IEEE Trans. Wireless Comm., vol. 4, no. 4, pp. 1779-1788, July 2005.
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