Real-time Phase Tracking Method for IEEE 802.11a/g/n Receiver under Phase Noise Condition

Sakata, Ren; Akita, Koji; Sato, Ken-ichi

doi:10.1109/vetecs.2006.1683187

Cited by 3 publications

(3 citation statements)

References 14 publications

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“…However the receiver still experiences phase offsets in the frequency domain due to the residual CFO. We use an adaptation of the scheme proposed in [17] to track and correct these errors. These systems (time-domain CFO correction and frequency-domain phase correction) are used during receptions of both non-cooperative and cooperative transmissions.…”

Section: B Carrier Frequency Offsetmentioning

confidence: 99%

Design, Implementation, and Characterization of a Cooperative Communications System

Murphy

Sabharwal

2011

IEEE Trans. Veh. Technol.

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Cooperative communications is a class of techniques which seek to improve reliability and throughput in wireless systems by pooling the resources of distributed nodes. While cooperation can occur at different network layers and time scales, physical layer cooperation at symbol time scales offers the largest benefit in combating losses due to fading. However, symbol level cooperation poses significant implementation challenges, especially in synchronizing the behaviors and carrier frequencies of distributed nodes.We present the implementation and characterization of a complete, real-time cooperative physical layer transceiver built on the Rice Wireless Open-Access Research Platform (WARP). In our implementation autonomous nodes employ physical layer cooperation without a central synchronization source, and are capable of selecting between non-cooperative and cooperative communication per packet. Cooperative transmissions use a distributed Alamouti space-time block code and employ either amplify-and-forward or decode-and-forward relaying.We also present experimental results of our transceiver's real-time performance under a variety of topologies and propagation conditions. Our results clearly demonstrate significant performance gains (more than 40× improvement in PER in some topologies) provided by physical layer cooperation, even when subject to the constraints of a real-time implementation. Finally, we present methodologies to isolate and understand the sources of performance bottlenecks in our design.As with all our work on WARP, our transceiver design and experimental framework are available via the open-source WARP repository for use by other wireless researchers.

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Section: B Carrier Frequency Offsetmentioning

confidence: 99%

Design, Implementation, and Characterization of a Cooperative Communications System

Murphy

Sabharwal

2011

IEEE Trans. Veh. Technol.

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“…Due to the buffering delay, the channel estimation method we described above could not provide an up-to-date phase estimate for the symbols to be equalized. Pilot-based phase tracking methods for IEEE 802.11 systems have been discussed in [18], [19]. However, the traditional pilot-aided phase tracking has poor performance due to the small number of pilot sub-carriers in IEEE 802.11p systems.…”

Section: Channel-estimate-based Phase Trackingmentioning

confidence: 99%

Implementation and evaluation of channel estimation and phase tracking for vehicular networks

Rajan

Camp

2013

2013 9th International Wireless Communications and Mobile Computing Conference (IWCMC)

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The high mobility of vehicular networks makes channel estimation and phase tracking challenging and an important problem for OFDM receiver design. In IEEE 802.11p vehicular networks, the channel estimation based on a long preamble in the PHY frame performs poorly in fast-fading channels. Moreover, the pilot-based phase tracking usually suffers from large residual phase errors. In this paper, we propose and implement a novel phase tracking algorithm, leveraging the decoded data. We also provide a detailed hardware design for a decoder-based channel estimation algorithm with a pipeline structure on an FPGA-based platform. Through diverse experiments via an advanced channel emulator, our results show that the proposed algorithm could significantly improve the system performance in terms of packet error rate, while adding less than 3% of additional hardware resources. We also jointly evaluate the packet error rate versus the bitwidth of the data in the FPGA, which is important to achieve a good balance between the hardware cost and the system performance.

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“…Our OFDM receiver uses standard techniques for compensating for carrier offsets and phase noise [6,7]. The effects are compounded when two nodes with different carrier frequency offsets are transmitting simultaneously to a common destination.…”

Section: ) Automatic Response Processingmentioning

confidence: 99%

Design of a cooperative OFDM transceiver

Murphy

Hunter

Sabharwal

2009

2009 Conference Record of the Forty-Third Asilomar Conference on Signals, Systems and Computers

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Abstract-We present the FPGA implementation of a MIMO and cooperative OFDM physical layer transceiver. Our transceiver is designed to support multiple antenna configurations, including SISO (single-antenna), receive switching diversity, transmit diversity using Alamouti's space-time block code and 2x2 spatial multiplexing. It also supports a fully-distributed physical layer cooperation scheme which allows two nodes to simultaneously transmit a common payload, achieving spatial diversity with only single-antenna transmissions. Our transceiver supports the common cooperative scheme of amplify-and-forward and provides a flexible interface for higher layers to enable cooperation as needed. The transceiver is implemented as a single FPGA core with a common datapath for all modes. This allows both efficient resource reuse between modes and a per-packet selection of antenna mode. This flexibility enables a wide variety of MIMO and cooperative protocols. We present architectural details of the cooperative transceiver design and early performance results using Rice University's Wireless Open-Access Research Platform (WARP).

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Real-time Phase Tracking Method for IEEE 802.11a/g/n Receiver under Phase Noise Condition

Cited by 3 publications

References 14 publications

Design, Implementation, and Characterization of a Cooperative Communications System

Design, Implementation, and Characterization of a Cooperative Communications System

Implementation and evaluation of channel estimation and phase tracking for vehicular networks

Design of a cooperative OFDM transceiver

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