The Experts below are selected from a list of 40281 Experts worldwide ranked by ideXlab platform
Narayan B Mandayam - One of the best experts on this subject based on the ideXlab platform.
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uplink linear Receivers for multi cell multiuser mimo with pilot contamination large system analysis
IEEE Transactions on Wireless Communications, 2014Co-Authors: Narayanan Krishnan, Roy D Yates, Narayan B MandayamAbstract:Base stations with a large number of transmit antennas can potentially serve a large number of users at high rates. However, the Receiver Processing in the uplink relies on channel estimates, which are known to suffer from pilot interference. In this paper, making use of the similarity of the uplink received signal in CDMA with that of a multi-cell multi-antenna system, we perform a large system analysis when the Receiver employs an MMSE filter with a pilot contaminated estimate. We assume a Rayleigh fading channel with different received powers from users. We find the asymptotic signal to interference plus noise ratio (SINR) as the number of antennas and number of users per base station grow larger while maintaining a fixed ratio. Through the SINR expression we explore the scenario where the number of users being served are comparable to the number of antennas at the base station. The SINR explicitly captures the effect of pilot contamination and is found to be the same as that employing a matched filter with a pilot contaminated estimate. We also find the exact expression for the interference suppression obtained using an MMSE filter, which is an important factor when there are a significant number of users in the system as compared to the number of antennas. In a typical set up, in terms of the five percentile SINR, the MMSE filter is shown to provide significant gains over matched filtering and is within 5 dB of MMSE filter with perfect channel estimate. Simulation results for achievable rates are close to large system limits for even a 10-antenna base station with 3 or more users per cell.
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uplink linear Receivers for multi cell multiuser mimo with pilot contamination large system analysis
arXiv: Information Theory, 2013Co-Authors: Narayanan Krishnan, Roy D Yates, Narayan B MandayamAbstract:Base stations with a large number of transmit antennas have the potential to serve a large number of users at high rates. However, the Receiver Processing in the uplink relies on channel estimates which are known to suffer from pilot interference. In this work, making use of the similarity of the uplink received signal in CDMA with that of a multi-cell multi-antenna system, we perform a large system analysis when the Receiver employs an MMSE filter with a pilot contaminated estimate. We assume a Rayleigh fading channel with different received powers from users. We find the asymptotic Signal to Interference plus Noise Ratio (SINR) as the number of antennas and number of users per base station grow large while maintaining a fixed ratio. Through the SINR expression we explore the scenario where the number of users being served are comparable to the number of antennas at the base station. The SINR explicitly captures the effect of pilot contamination and is found to be the same as that employing a matched filter with a pilot contaminated estimate. We also find the exact expression for the interference suppression obtained using an MMSE filter which is an important factor when there are significant number of users in the system as compared to the number of antennas. In a typical set up, in terms of the five percentile SINR, the MMSE filter is shown to provide significant gains over matched filtering and is within 5 dB of MMSE filter with perfect channel estimate. Simulation results for achievable rates are close to large system limits for even a 10-antenna base station with 3 or more users per cell.
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cellular systems with many antennas large system analysis under pilot contamination
Allerton Conference on Communication Control and Computing, 2012Co-Authors: Narayanan Krishnan, Roy D Yates, Narayan B MandayamAbstract:Base stations with a large number of transmit antennas have the potential to serve a large number of users simultaneously at higher rates. They also promise a lower power consumption due to coherent combining at the Receiver. However, the Receiver Processing in the uplink relies on the channel estimates which are known to suffer from pilot interference. In this work, we perform an uplink large system analysis of multi-cell multi-antenna system when the Receiver employs a matched filtering with a pilot contaminated estimate. We find the asymptotic Signal to Interference plus Noise Ratio (SINR) as the number of antennas and number of users per base station grow large while maintaining a fixed ratio. To do this, we make use of the similarity of the uplink received signal in a multi-antenna system to the representation of the received signal in CDMA systems. The asymptotic SINR expression explicitly captures the effect of pilot contamination and that of interference averaging. This also explains the SINR performance of Receiver Processing schemes at different regimes such as instances when the number of antennas are comparable to number of users as well as when antennas exceed greatly the number of users. Finally, we also propose that the adaptive MMSE symbol detection scheme, which does not require the explicit channel knowledge, can be employed for cellular systems with large number of antennas.
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software defined radio architectures for interference cancellation in ds cdma systems
IEEE Personal Communications, 1999Co-Authors: Ivan Seskar, Narayan B MandayamAbstract:Third-generation wireless systems call for strategies that can improve achievable performance and data rates while providing flexibility and affordability. Software-defined radio technology is promising to provide the required flexibility in radio frequency, intermediate frequency, and baseband signal Processing stages. Baseband signal Processing techniques such as interference cancellation for direct-sequence code-division multiple access systems have the potential to provide the higher performance requirements of 3G systems. With advances in digital signal processor technology, the gap between the complexity of interference cancellation algorithms and available Processing speeds is narrowing. However, 3G system requirements are ever pushing the envelope of signal Processing algorithms required, including multi-user detection schemes, that are considered to be attractive and viable candidates. WINLAB has been working on an attractive SDR solution, to provide flexibility and handle the Processing speeds required of 3G radio Receivers. The approach is based on SDR architectures that partition radio Receiver Processing into two core technologies (field programmable gate arrays and DSP devices). We present a summary of the SDR work at WINLAB that is based on using this mixed signal Processing approach for implementation of nonlinear interference cancellation and linear multi-user detection algorithms.
Michael Lhamon - One of the best experts on this subject based on the ideXlab platform.
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a new multichannel coherent amplitude modulated time division multiplexed software defined radio Receiver architecture and field programmable gate array technology implementation
IEEE Transactions on Signal Processing, 2010Co-Authors: Veerendra Bhargav Alluri, Robert J Heath, Michael LhamonAbstract:Some wireless communication systems must be able to receive and process signals from multiple source stations simultaneously. A common practice is to use multiple duplicated hardware resources; a different set of resources for each received station. A new coherent amplitude modulated (AM), time-division multiplexed (TDM), Receiver system architecture and design, based on the software-defined radio (SDR) standard, is proposed, developed and validated via simulation and experimental hardware prototype testing. The new Receiver system architecture and approach enables reception and Processing of signals from multiple stations using the hardware resources normally needed for reception and Processing of only one station. Production models of the proposed Receiver/Processing system architecture and design would be implemented in programmable-logic-device (PLD) technology [field-programmable-gate-array (FPGA) in our case] to accommodate rapidly changing communication protocols and standards and to enhance Processing performance.
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a multi channel coherent amplitude modulated time division multiplexed software defined radio Receiver architecture for programmable logic device technology implementation
Radio and Wireless Symposium, 2009Co-Authors: Bhargav V Alluri, Robert J Heath, Michael LhamonAbstract:Some wireless communication systems must be able to receive and process signals from multiple source channels (stations) simultaneously. A common practice is to use multiple duplicated hardware resources; a different set of resources for each received channel. A new coherent Amplitude Modulated (AM) Time Division Multiplexed (TDM) Receiver system architecture and design, based on the Software Defined Radio (SDR) standard, is proposed, developed and validated via simulation and experimental hardware prototype testing. The new Receiver system architecture and approach enables reception and Processing of signals from multiple channels using the hardware resources normally needed for reception and Processing of only one channel. Production models of the proposed Receiver/Processing system architecture and design would be implemented to Programmable-Logic-Device (PLD) technology to accommodate rapidly changing communication protocols and standards and to enhance Processing performance.
Narayanan Krishnan - One of the best experts on this subject based on the ideXlab platform.
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uplink linear Receivers for multi cell multiuser mimo with pilot contamination large system analysis
IEEE Transactions on Wireless Communications, 2014Co-Authors: Narayanan Krishnan, Roy D Yates, Narayan B MandayamAbstract:Base stations with a large number of transmit antennas can potentially serve a large number of users at high rates. However, the Receiver Processing in the uplink relies on channel estimates, which are known to suffer from pilot interference. In this paper, making use of the similarity of the uplink received signal in CDMA with that of a multi-cell multi-antenna system, we perform a large system analysis when the Receiver employs an MMSE filter with a pilot contaminated estimate. We assume a Rayleigh fading channel with different received powers from users. We find the asymptotic signal to interference plus noise ratio (SINR) as the number of antennas and number of users per base station grow larger while maintaining a fixed ratio. Through the SINR expression we explore the scenario where the number of users being served are comparable to the number of antennas at the base station. The SINR explicitly captures the effect of pilot contamination and is found to be the same as that employing a matched filter with a pilot contaminated estimate. We also find the exact expression for the interference suppression obtained using an MMSE filter, which is an important factor when there are a significant number of users in the system as compared to the number of antennas. In a typical set up, in terms of the five percentile SINR, the MMSE filter is shown to provide significant gains over matched filtering and is within 5 dB of MMSE filter with perfect channel estimate. Simulation results for achievable rates are close to large system limits for even a 10-antenna base station with 3 or more users per cell.
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uplink linear Receivers for multi cell multiuser mimo with pilot contamination large system analysis
arXiv: Information Theory, 2013Co-Authors: Narayanan Krishnan, Roy D Yates, Narayan B MandayamAbstract:Base stations with a large number of transmit antennas have the potential to serve a large number of users at high rates. However, the Receiver Processing in the uplink relies on channel estimates which are known to suffer from pilot interference. In this work, making use of the similarity of the uplink received signal in CDMA with that of a multi-cell multi-antenna system, we perform a large system analysis when the Receiver employs an MMSE filter with a pilot contaminated estimate. We assume a Rayleigh fading channel with different received powers from users. We find the asymptotic Signal to Interference plus Noise Ratio (SINR) as the number of antennas and number of users per base station grow large while maintaining a fixed ratio. Through the SINR expression we explore the scenario where the number of users being served are comparable to the number of antennas at the base station. The SINR explicitly captures the effect of pilot contamination and is found to be the same as that employing a matched filter with a pilot contaminated estimate. We also find the exact expression for the interference suppression obtained using an MMSE filter which is an important factor when there are significant number of users in the system as compared to the number of antennas. In a typical set up, in terms of the five percentile SINR, the MMSE filter is shown to provide significant gains over matched filtering and is within 5 dB of MMSE filter with perfect channel estimate. Simulation results for achievable rates are close to large system limits for even a 10-antenna base station with 3 or more users per cell.
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cellular systems with many antennas large system analysis under pilot contamination
Allerton Conference on Communication Control and Computing, 2012Co-Authors: Narayanan Krishnan, Roy D Yates, Narayan B MandayamAbstract:Base stations with a large number of transmit antennas have the potential to serve a large number of users simultaneously at higher rates. They also promise a lower power consumption due to coherent combining at the Receiver. However, the Receiver Processing in the uplink relies on the channel estimates which are known to suffer from pilot interference. In this work, we perform an uplink large system analysis of multi-cell multi-antenna system when the Receiver employs a matched filtering with a pilot contaminated estimate. We find the asymptotic Signal to Interference plus Noise Ratio (SINR) as the number of antennas and number of users per base station grow large while maintaining a fixed ratio. To do this, we make use of the similarity of the uplink received signal in a multi-antenna system to the representation of the received signal in CDMA systems. The asymptotic SINR expression explicitly captures the effect of pilot contamination and that of interference averaging. This also explains the SINR performance of Receiver Processing schemes at different regimes such as instances when the number of antennas are comparable to number of users as well as when antennas exceed greatly the number of users. Finally, we also propose that the adaptive MMSE symbol detection scheme, which does not require the explicit channel knowledge, can be employed for cellular systems with large number of antennas.
Veerendra Bhargav Alluri - One of the best experts on this subject based on the ideXlab platform.
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a new multichannel coherent amplitude modulated time division multiplexed software defined radio Receiver architecture and field programmable gate array technology implementation
IEEE Transactions on Signal Processing, 2010Co-Authors: Veerendra Bhargav Alluri, Robert J Heath, Michael LhamonAbstract:Some wireless communication systems must be able to receive and process signals from multiple source stations simultaneously. A common practice is to use multiple duplicated hardware resources; a different set of resources for each received station. A new coherent amplitude modulated (AM), time-division multiplexed (TDM), Receiver system architecture and design, based on the software-defined radio (SDR) standard, is proposed, developed and validated via simulation and experimental hardware prototype testing. The new Receiver system architecture and approach enables reception and Processing of signals from multiple stations using the hardware resources normally needed for reception and Processing of only one station. Production models of the proposed Receiver/Processing system architecture and design would be implemented in programmable-logic-device (PLD) technology [field-programmable-gate-array (FPGA) in our case] to accommodate rapidly changing communication protocols and standards and to enhance Processing performance.
Robert J Heath - One of the best experts on this subject based on the ideXlab platform.
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a new multichannel coherent amplitude modulated time division multiplexed software defined radio Receiver architecture and field programmable gate array technology implementation
IEEE Transactions on Signal Processing, 2010Co-Authors: Veerendra Bhargav Alluri, Robert J Heath, Michael LhamonAbstract:Some wireless communication systems must be able to receive and process signals from multiple source stations simultaneously. A common practice is to use multiple duplicated hardware resources; a different set of resources for each received station. A new coherent amplitude modulated (AM), time-division multiplexed (TDM), Receiver system architecture and design, based on the software-defined radio (SDR) standard, is proposed, developed and validated via simulation and experimental hardware prototype testing. The new Receiver system architecture and approach enables reception and Processing of signals from multiple stations using the hardware resources normally needed for reception and Processing of only one station. Production models of the proposed Receiver/Processing system architecture and design would be implemented in programmable-logic-device (PLD) technology [field-programmable-gate-array (FPGA) in our case] to accommodate rapidly changing communication protocols and standards and to enhance Processing performance.
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a multi channel coherent amplitude modulated time division multiplexed software defined radio Receiver architecture for programmable logic device technology implementation
Radio and Wireless Symposium, 2009Co-Authors: Bhargav V Alluri, Robert J Heath, Michael LhamonAbstract:Some wireless communication systems must be able to receive and process signals from multiple source channels (stations) simultaneously. A common practice is to use multiple duplicated hardware resources; a different set of resources for each received channel. A new coherent Amplitude Modulated (AM) Time Division Multiplexed (TDM) Receiver system architecture and design, based on the Software Defined Radio (SDR) standard, is proposed, developed and validated via simulation and experimental hardware prototype testing. The new Receiver system architecture and approach enables reception and Processing of signals from multiple channels using the hardware resources normally needed for reception and Processing of only one channel. Production models of the proposed Receiver/Processing system architecture and design would be implemented to Programmable-Logic-Device (PLD) technology to accommodate rapidly changing communication protocols and standards and to enhance Processing performance.
