ABSTRACT
This paper presents SoftRate, a wireless bit rate adaptation protocol that is responsive to rapidly varying channel conditions. Unlike previous work that uses either frame receptions or signal-to-noise ratio (SNR) estimates to select bit rates, SoftRate uses confidence information calculated by the physical layer and exported to higher layers via the SoftPHY interface to estimate the prevailing channel bit error rate (BER). Senders use this BER estimate, calculated over each received packet (even when the packet has no bit errors), to pick good bit rates. SoftRate's novel BER computation works across different wireless environments and hardware without requiring any retraining. SoftRate also uses abrupt changes in the BER estimate to identify interference, enabling it to reduce the bit rate only in response to channel errors caused by attenuation or fading. Our experiments conducted using a software radio prototype show that SoftRate achieves 2X higher throughput than popular frame-level protocols such as SampleRate and RRAA. It also achieves 20% more throughput than an SNR-based protocol trained on the operating environment, and up to 4X higher throughput than an untrained SNR-based protocol. The throughput gains using SoftRate stem from its ability to react to channel variations within a single packet-time and its robustness to collision losses.
- P. A. K. Acharya, A. Sharma, E. M. Belding, K. C. Almeroth, and D. Papagiannaki. Congestion-Aware Rate Adaptation in Wireless Networks: A Measurement-Driven Approach. In Proc. IEEE SECON Conf., pp. 1--9, San Francisco, CA, June 2008.Google ScholarCross Ref
- L. Bahl, J. Cocke, F. Jelinek, and J. Raviv. Optimal Decoding of Linear Codes for Minimizing Symbol Error Rate (Corresp.). IEEE Trans. on Information Theory, 20(2):284--287, 1974.Google ScholarDigital Library
- S. Biaz and N. H. Vaidya. Discriminating Congestion Losses from Wireless Losses Using Inter-arrival Times at the Receiver. In Proc. of the IEEE ASSET Symp., pp. 10--17, Richardson, TX, Mar. 1999. Google ScholarDigital Library
- J. Bicket. Bit-Rate Selection in Wireless Networks. Master's thesis, Massachusetts Institute of Technology, Feb. 2005.Google Scholar
- J. Camp and E. Knightly. Modulation Rate Adaptation in Urban and Vehicular Environments: Cross-Layer Implementation and Experimental Evaluation. In Proc. of the ACM MobiCom Conf., pp. 315--326, San Francisco, CA, Sept. 2008. Google ScholarDigital Library
- G. D. Forney, Jr. The Viterbi Algorithm (Invited Paper). Proc. of the IEEE, 61(3):268--278, Mar. 1973.Google ScholarCross Ref
- S. Gollakota and D. Katabi. Zigzag Decoding: Combating Hidden Terminals in Wireless Networks. In Proc. of the ACM SIGCOMM Conf., pp. 159--170, Seattle, WA, Aug. 2008. Google ScholarDigital Library
- J. Hagenauer and P. Hoeher. A Viterbi Algorithm with Soft-Decision Outputs and its Applications. In Proc. IEEE GLOBECOM, pp. 1680--1686, Dallas, TX, Nov. 1989.Google ScholarCross Ref
- D. Halperin, T. Anderson, and D. Wetherall. Taking the Sting out of Carrier Sense: Interference Canncelation for Wireless LANs. In ACM MobiCom, pp. 339--350, San Francisco, CA, Sept. 2008. Google ScholarDigital Library
- G. Holland, N. Vaidya, and P. Bahl. A Rate-Adaptive MAC Protocol for Multihop Wireless Networks. In Proc. of ACM MobiCom Conf., pp. 236--251, Rome, Italy, Sept. 2001. Google ScholarDigital Library
- IEEE Standard 802.16e-2005: Air Interface for Fixed and Mobile Broadband Wireless Access Systems, Amendment 2, Feb. 2006. http://standards.ieee.org/getieee802/802.16.html.Google Scholar
- K. Jamieson and H. Balakrishnan. PPR: Partial Packet Recovery for Wireless Networks. In Proc. ACM SIGCOMM, pp. 409--420, Kyoto, Japan, August 2007. Google ScholarDigital Library
- G. Judd, X. Wang, and P. Steenkiste. Efficient Channel-aware Rate Adaptation in Dynamic Environments. In Proc. of the ACM MobiSys Conf., pp. 118--131, Breckenridge, CO, June 2008. Google ScholarDigital Library
- A. Kamerman and L. Monteban. WaveLAN II: a High-Performance Wireless LAN for the Unlicensed Band. Bell Labs Technical Journal, 2(3):118--133, Summer 1997.Google ScholarCross Ref
- K. C. Lin, N. Kushman, and D. Katabi. ZipTx: Exploiting the Gap Between Bit Errors and Packet Loss. In Proc. of the ACM MobiCom Conf., pp. 351--362, San Francisco, CA, Sept. 2008.Google ScholarDigital Library
- D. Mandelbaum. An Adaptive-Feedback Coding Scheme Using Incremental Redundancy (Corresp.). IEEE Trans. on Information Theory, 20(3):388--389, May 1974.Google ScholarDigital Library
- J. Metzner. Improvements in Block--Retransmission Schemes. IEEE Trans. on Communications, 27(2):524--532, Feb. 1979.Google ScholarCross Ref
- ONOE Rate Control. http://madwifi.org/browser/trunk/ath_rate/onoe.Google Scholar
- J. G. Proakis. Digital Communications, 4th ed. McGraw-Hill, 2000.Google Scholar
- S. Rayanchu, A. Mishra, D. Agrawal, S. Saha, and S. Banerjee. Diagnosing Wireless Packet Losses in 802.11: Separating Collision from Weak Signal. In Proc. of IEEE INFOCOM Conf., pp. 735--743, Phoenix, AZ, Apr. 2008.Google ScholarCross Ref
- B. Sadeghi, V. Kanodia, A. Sabharwal, and E. Knightly. Opportunistic Media Access for Multirate Ad Hoc Networks. In Proc. of ACM MobiCom Conf., pp. 24--35, Atlanta, GA, Sept. 2002. Google ScholarDigital Library
- T. M. Schmidl and D. C. Cox. Robust Frequency and Timing Synchroniation for OFDM. IEEE Trans. on Communications., 45:1613--1621, Dec. 1997.Google ScholarCross Ref
- D. Tse and P. Viswanath. Fundamentals of Wireless Communication. Cambridge Univ. Press, 2005. Google ScholarDigital Library
- S. Wong, H. Yang, S. Lu, and V. Bharghavan. Robust Rate Adaptation for 802.11 Wireless Networks. In Proc. of ACM MobiCom Conf., pp. 146--157, Los Angeles, CA, Sept. 2006. Google ScholarDigital Library
- J. Zhang, K. Tan, J. Zhao, H. Wu, and Y. Zhang. A Practical SNR-Guided Rate Adaptation. In Proc. of the IEEE INFOCOM Conf., pp. 2083--2091, Phoenix, AZ, Apr. 2008.Google ScholarCross Ref
- Y. Zheng and C. Xiao. Simulation Models With Correct Statistical Properties for Rayleigh Fading Channels. IEEE Trans. on Communications, 51(6):920--928, 2003.Google ScholarCross Ref
Index Terms
- Cross-layer wireless bit rate adaptation
Recommendations
Cross-layer wireless bit rate adaptation
SIGCOMM '09This paper presents SoftRate, a wireless bit rate adaptation protocol that is responsive to rapidly varying channel conditions. Unlike previous work that uses either frame receptions or signal-to-noise ratio (SNR) estimates to select bit rates, SoftRate ...
Cross-layer based transmit antenna selection for decision-feedback detection in correlated Ricean MIMO channels
In this paper, we investigate a cross-layer transmit antenna selection (AS) approach for the decision-feedback detector (DFD) over spatially correlated flat Ricean fading multiple-input multiple-output (MIMO) channels. Closed-form expressions for the ...
Wireless multimedia delivery over 802.11e with cross-layer optimization techniques
The use of wireless networks has spread further than simple data transfer to delay sensitive and loss tolerant multimedia applications. Over the past few years, wireless multimedia transmission across Wireless Local area Networks (WLANs) has gained a ...
Comments