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Jean-claude Belfiore - One of the best experts on this subject based on the ideXlab platform.

  • optimal space time codes for the mimo amplify and forward cooperative channel
    IEEE Transactions on Information Theory, 2007
    Co-Authors: Sheng Yang, Jean-claude Belfiore
    Abstract:

    In this work, we extend the nonorthogonal amplify-and-forward (NAF) cooperative Diversity Scheme to the multiple-input multiple-output (MIMO) channel. A family of space-time block codes for a half-duplex MIMO NAF fading cooperative channel with N relays is constructed. The code construction is based on the nonvanishing determinant (NVD) criterion and is shown to achieve the optimal Diversity-multiplexing tradeoff (DMT) of the channel. We provide a general explicit algebraic construction, followed by some examples. In particular, in the single-relay case, it is proved that the Golden code and the 4times4 Perfect code are optimal for the single-antenna and two-antenna cases, respectively. Simulation results reveal that a significant gain (up to 10 dB) can be obtained with the proposed codes, especially in the single-antenna case

  • Towards the Optimal Amplify-and-Forward Cooperative Diversity Scheme
    IEEE Transactions on Information Theory, 2007
    Co-Authors: Sheng Yang, Jean-claude Belfiore
    Abstract:

    In a slow-fading channel, how to find a cooperative Diversity Scheme that achieves the transmit Diversity bound is still an open problem. In fact, all previously proposed amplify-and-forward (AF) and decode-and-forward (DF) Schemes do not improve with the number of relays in terms of the Diversity-multiplexing tradeoff (DMT) for multiplexing gains r higher than 0.5. In this work, the class of slotted amplify-and-forward (SAF) Schemes is studied. First, an upper bound on the DMT for any SAF Scheme with an arbitrary number of relays N and number of slots M is established. Then, a sequential SAF Scheme that can exploit the potential Diversity gain in the high multiplexing gain regime is proposed. More precisely, in certain conditions, the sequential SAF Scheme achieves the proposed DMT upper bound which tends to the transmit Diversity bound when M goes to infinity. In particular, for the two-relay case, the three-slot sequential SAF Scheme achieves the proposed upper bound and outperforms the two-relay nonorthorgonal amplify-and-forward (NAF) Scheme of Azarian for multiplexing gains r les 2/3. Numerical results reveal a significant gain of our Scheme over the previously proposed AF Schemes, especially in high spectral efficiency and large network size regime.

  • towards the optimal amplify and forward cooperative Diversity Scheme
    arXiv: Information Theory, 2006
    Co-Authors: Sheng Yang, Jean-claude Belfiore
    Abstract:

    In a slow fading channel, how to find a cooperative Diversity Scheme that achieves the transmit Diversity bound is still an open problem. In fact, all previously proposed amplify-and-forward (AF) and decode-and-forward (DF) Schemes do not improve with the number of relays in terms of the Diversity multiplexing tradeoff (DMT) for multiplexing gains r higher than 0.5. In this work, we study the class of slotted amplify-and-forward (SAF) Schemes. We first establish an upper bound on the DMT for any SAF Scheme with an arbitrary number of relays N and number of slots M. Then, we propose a sequential SAF Scheme that can exploit the potential Diversity gain in the high multiplexing gain regime. More precisely, in certain conditions, the sequential SAF Scheme achieves the proposed DMT upper bound which tends to the transmit Diversity bound when M goes to infinity. In particular, for the two-relay case, the three-slot sequential SAF Scheme achieves the proposed upper bound and outperforms the two-relay non-orthorgonal amplify-and-forward (NAF) Scheme of Azarian et al. for multiplexing gains r < 2/3. Numerical results reveal a significant gain of our Scheme over the previously proposed AF Schemes, especially in high spectral efficiency and large network size regime.

  • optimal space time codes for the mimo amplify and forward cooperative channel
    arXiv: Information Theory, 2005
    Co-Authors: Sheng Yang, Jean-claude Belfiore
    Abstract:

    In this work, we extend the non-orthogonal amplify-and-forward (NAF) cooperative Diversity Scheme to the MIMO channel. A family of space-time block codes for a half-duplex MIMO NAF fading cooperative channel with N relays is constructed. The code construction is based on the non-vanishing determinant criterion (NVD) and is shown to achieve the optimal Diversity-multiplexing tradeoff (DMT) of the channel. We provide a general explicit algebraic construction, followed by some examples. In particular, in the single relay case, it is proved that the Golden code and the 4x4 Perfect code are optimal for the single-antenna and two-antenna case, respectively. Simulation results reveal that a significant gain (up to 10dB) can be obtained with the proposed codes, especially in the single-antenna case.

Vincent H Poor - One of the best experts on this subject based on the ideXlab platform.

  • a cluster based transmit Diversity Scheme for asynchronous joint transmissions in private networks
    International Conference on Communications, 2021
    Co-Authors: Kyeong Jin Kim, Philip Orlik, Jianlin Guo, Yukimasa Nagai, Vincent H Poor
    Abstract:

    In this paper, a multiple cluster-based transmission Diversity Scheme is proposed for asynchronous joint transmissions (JT) in private networks, in which the use of multiple clusters or small cells is preferable to increase transmission speeds, reduce latency, and bring transmissions closer to the users. To increase the spectral efficiency and coverage, and to achieve flexible spatial degrees of freedom, a distributed remote radio unit system (dRRUS) is installed in each of the clusters. When the dRRUS is disposed in the private environments, it will be associated with multipath-rich and asynchronous delay propagation. Taking into account of this unique environment of private networks, asynchronous multiple signal reception is considered in the development of operation at the remote radio units to make an intersymbol interference free distributed cyclic delay Diversity (dCDD) Scheme for JT to achieve a full transmit Diversity gain without full channel state information. A spectral efficiency of the proposed dCDD-based JT is analyzed by deriving the closed- form expression, and then compared with link-level simulations for non-identically distributed frequency selective fading over the entire private network.

  • a dcdd based transmit Diversity Scheme for downlink pseudo noma systems
    IEEE Transactions on Wireless Communications, 2021
    Co-Authors: Kyeong Jin Kim, Hongwu Liu, Hongjiang Lei, Zhiguo Ding, Philip Orlik, Vincent H Poor
    Abstract:

    In this paper, a new transmit Diversity Scheme is proposed for cooperative pseudo-non-orthogonal multiple access (Pseudo-NOMA) without assuming full channel state information at the transmitter (CSIT). To support two users under the near-far user pairing constraint, a distributed cyclic delay Diversity (dCDD) Scheme is adapted into NOMA by dividing a set of remote radio heads (RRHs) into two groups for multiple cyclic-prefixed single carrier transmissions. To maximize a far user’s rate and two users’ sum rate over independently but non-identically distributed frequency selective fading channels and under a near-far user pairing constraint, we first derive closed-form expressions for the rates of the two users with full CSIT. Considering that only partial CSIT is available, a new RRH assignment and power allocation Scheme is proposed for dCDD-Pseudo-NOMA. For various simulation scenarios, the provided link-level simulations verify that higher rates can be achieved by dCDD-Pseudo-NOMA compared with the traditional orthogonal multiple access with dCDD and dCDD-Conventional-NOMA that uses the superimposed signals. Furthermore, the proposed RRH assignment and power allocation Scheme makes dCDD-Pseudo-NOMA achieve almost the same rate as that of ideal dCDD-Pseudo-NOMA which requires full CSIT.

  • outage probability analysis of spectrum sharing systems with distributed cyclic delay Diversity
    IEEE Transactions on Communications, 2019
    Co-Authors: Kyeong Jin Kim, Marco Di Renzo, Hongwu Liu, Miaowen Wen, Vincent H Poor
    Abstract:

    In this paper, a distributed cognitive underlay single carrier system is investigated. A secondary users’ network consists of a control unit (CU) and a group of secondary user remote radio heads (S-RRHs). To effectively access the radio spectrum licensed to the primary users, a distributed cyclic delay Diversity (dCDD) Scheme is employed between the CU and S-RRHs as the transmit Diversity Scheme. Multiple primary user transmitters (PTXs) are assumed to be located isotropically within the secondary users’ network, so that a mixture of line-of-sight (LoS) and non-line-of-sight (nLoS) paths from the PTXs to the secondary user receiver is considered. In addition, a mixture of LoS and nLoS paths is considered in the secondary users’ network. For a new transmit Diversity Scheme and channel model, the performance of the secondary users’ network achieved by the dCDD in the presence of isotropically distributed multiple PTXs is investigated. The dCDD enables the CU to use multiple S-RRHs at the same time, so that determining the effects of a different number of S-RRHs in the presence of a new channel model is an open research issue. To this end, a new closed-form expression for the outage probability is derived, and then its accuracy is verified by link-level simulations.

Sheng Yang - One of the best experts on this subject based on the ideXlab platform.

  • optimal space time codes for the mimo amplify and forward cooperative channel
    IEEE Transactions on Information Theory, 2007
    Co-Authors: Sheng Yang, Jean-claude Belfiore
    Abstract:

    In this work, we extend the nonorthogonal amplify-and-forward (NAF) cooperative Diversity Scheme to the multiple-input multiple-output (MIMO) channel. A family of space-time block codes for a half-duplex MIMO NAF fading cooperative channel with N relays is constructed. The code construction is based on the nonvanishing determinant (NVD) criterion and is shown to achieve the optimal Diversity-multiplexing tradeoff (DMT) of the channel. We provide a general explicit algebraic construction, followed by some examples. In particular, in the single-relay case, it is proved that the Golden code and the 4times4 Perfect code are optimal for the single-antenna and two-antenna cases, respectively. Simulation results reveal that a significant gain (up to 10 dB) can be obtained with the proposed codes, especially in the single-antenna case

  • Towards the Optimal Amplify-and-Forward Cooperative Diversity Scheme
    IEEE Transactions on Information Theory, 2007
    Co-Authors: Sheng Yang, Jean-claude Belfiore
    Abstract:

    In a slow-fading channel, how to find a cooperative Diversity Scheme that achieves the transmit Diversity bound is still an open problem. In fact, all previously proposed amplify-and-forward (AF) and decode-and-forward (DF) Schemes do not improve with the number of relays in terms of the Diversity-multiplexing tradeoff (DMT) for multiplexing gains r higher than 0.5. In this work, the class of slotted amplify-and-forward (SAF) Schemes is studied. First, an upper bound on the DMT for any SAF Scheme with an arbitrary number of relays N and number of slots M is established. Then, a sequential SAF Scheme that can exploit the potential Diversity gain in the high multiplexing gain regime is proposed. More precisely, in certain conditions, the sequential SAF Scheme achieves the proposed DMT upper bound which tends to the transmit Diversity bound when M goes to infinity. In particular, for the two-relay case, the three-slot sequential SAF Scheme achieves the proposed upper bound and outperforms the two-relay nonorthorgonal amplify-and-forward (NAF) Scheme of Azarian for multiplexing gains r les 2/3. Numerical results reveal a significant gain of our Scheme over the previously proposed AF Schemes, especially in high spectral efficiency and large network size regime.

  • towards the optimal amplify and forward cooperative Diversity Scheme
    arXiv: Information Theory, 2006
    Co-Authors: Sheng Yang, Jean-claude Belfiore
    Abstract:

    In a slow fading channel, how to find a cooperative Diversity Scheme that achieves the transmit Diversity bound is still an open problem. In fact, all previously proposed amplify-and-forward (AF) and decode-and-forward (DF) Schemes do not improve with the number of relays in terms of the Diversity multiplexing tradeoff (DMT) for multiplexing gains r higher than 0.5. In this work, we study the class of slotted amplify-and-forward (SAF) Schemes. We first establish an upper bound on the DMT for any SAF Scheme with an arbitrary number of relays N and number of slots M. Then, we propose a sequential SAF Scheme that can exploit the potential Diversity gain in the high multiplexing gain regime. More precisely, in certain conditions, the sequential SAF Scheme achieves the proposed DMT upper bound which tends to the transmit Diversity bound when M goes to infinity. In particular, for the two-relay case, the three-slot sequential SAF Scheme achieves the proposed upper bound and outperforms the two-relay non-orthorgonal amplify-and-forward (NAF) Scheme of Azarian et al. for multiplexing gains r < 2/3. Numerical results reveal a significant gain of our Scheme over the previously proposed AF Schemes, especially in high spectral efficiency and large network size regime.

  • optimal space time codes for the mimo amplify and forward cooperative channel
    arXiv: Information Theory, 2005
    Co-Authors: Sheng Yang, Jean-claude Belfiore
    Abstract:

    In this work, we extend the non-orthogonal amplify-and-forward (NAF) cooperative Diversity Scheme to the MIMO channel. A family of space-time block codes for a half-duplex MIMO NAF fading cooperative channel with N relays is constructed. The code construction is based on the non-vanishing determinant criterion (NVD) and is shown to achieve the optimal Diversity-multiplexing tradeoff (DMT) of the channel. We provide a general explicit algebraic construction, followed by some examples. In particular, in the single relay case, it is proved that the Golden code and the 4x4 Perfect code are optimal for the single-antenna and two-antenna case, respectively. Simulation results reveal that a significant gain (up to 10dB) can be obtained with the proposed codes, especially in the single-antenna case.

Mohamedslim Alouini - One of the best experts on this subject based on the ideXlab platform.

  • on the asymptotic throughput of the k th best secondary user selection in cognitive radio systems
    Vehicular Technology Conference, 2018
    Co-Authors: Yazan H Albadarneh, C N Georghiades, Mohamedslim Alouini
    Abstract:

    We analyze the asymptotic average and effective throughputs of a multiuser Diversity Scheme for a secondary multiuser network consisting of multiple secondary users (transmitters) and one secondary receiver. Considering a transmit power adaptation strategy at the secondary users to satisfy the instantaneous interference constraint at the primary receiver, the secondary receiver selects the $k$ -th best secondary user for transmission, namely, the one with the $k$ -th highest signal-to-noise ratio (SNR). We use extreme value theory to show that the $k$ -th highest SNR converges uniformly in distribution to an inverse gamma random variable for a fixed $k$ and large number of secondary users. We use this result to derive closed-form asymptotic expressions for the average and effective throughputs of the $k$ -th best secondary user.

  • Asymptotic Performance Analysis of the $k$ th Best Link Selection Over Wireless Fading Channels: An Extreme Value Theory Approach
    IEEE Transactions on Vehicular Technology, 2018
    Co-Authors: Yazan H. Al-badarneh, Costas N. Georghiades, Mohamedslim Alouini
    Abstract:

    We consider a general selection-Diversity Scheme in which the kth best link is selected from a number of links. We use extreme value theory to derive simple closed-form asymptotic expressions for the average throughput, effective throughput, and average bit error probability for the kth best link over various channel models that are widely used to characterize fading in wireless communication systems. As an application example, we consider the Weibull fading channel model and verify the accuracy of the derived asymptotic expressions through Monte Carlo simulations.

  • on the rate versus Diversity trade off in multi channel wireless transmission systems
    Wireless Communications and Networking Conference, 2007
    Co-Authors: Haewoon Nam, Mohamedslim Alouini
    Abstract:

    In this paper we first consider conventional multichannel systems with fixed-power variable-rate transmission of independent data streams as a function of channel variations. In the conventional systems, no data is transmitted through the channels whose received signal strength is below a certain cut off threshold. We then propose a new hybrid adaptive modulation and Diversity Scheme for multi-channel transmission systems. The proposed hybrid Scheme attempts to increase the overall spectral efficiency by (i) transmitting redundantly information symbols through the deeply faded channels that are not to be used in conventional multi-channel systems and then (ii) Diversity combining these signals at the receiver end. We calculate the spectral efficiency of the newly proposed hybrid Scheme and compare it to the spectral efficiency of (i) the conventional system and (ii) a benchmark optimal but complex joint adaptive and Diversity Scheme that maximizes the overall spectral efficiency. We show, with the help of some selected numerical examples, that the proposed hybrid Scheme offers almost the same spectral efficiency as the optimal Scheme with much reduced complexity.

  • postdetection switched combining a simple Diversity Scheme with improved ber performance
    IEEE Transactions on Communications, 2003
    Co-Authors: Mohamedslim Alouini, M K Simon
    Abstract:

    This paper develops, analyzes, and optimizes a simpler form of dual-branch switch-and-stay combining (SSC), namely, one that relies on the output signal plus noise rather than the instantaneous signal-to-noise ratio (SNR) to trigger the switching between the Diversity branches. Analysis supported by numerical results show that the newly proposed postdetection SSC Scheme outperforms predetection SSC and this performance gain increases as the channel conditions improve in terms of average SNR and/or severity of fading. In brief, when simplicity of implementation is of primary concern, as is the case, for example, in mobile units, the proposed Scheme offers an attractive low-complexity solution to mitigate the deleterious effects of multipath fading.

  • an mgf based performance analysis of generalized selection combining over rayleigh fading channels
    IEEE Transactions on Communications, 2000
    Co-Authors: Mohamedslim Alouini, M K Simon
    Abstract:

    Using the notion of the "spacing" between ordered exponential random variables, a performance analysis of the generalized selection combining (GSC) Diversity Scheme over Rayleigh fading channels is presented and compared with that of the conventional maximal-ratio combining and selection combining Schemes. Starting with the moment generating function (MGF) of the GSC output signal-to-noise ratio (SNR), we derive closed-form expressions for the average combined SNR, outage probability, and average error probability of a wide variety of modulation Schemes operating over independently, identically distributed (i.i.d.) Diversity paths. Because of their simple form, these expressions readily allow numerical evaluation for cases of practical interest. The results are also extended to the case of non-i.i.d. Diversity paths.

Jon W Mark - One of the best experts on this subject based on the ideXlab platform.

  • a cooperative Diversity Scheme based on quadrature signaling
    IEEE Transactions on Wireless Communications, 2007
    Co-Authors: V Mahinthan, Jon W Mark, Xuemin Shen
    Abstract:

    A bandwidth and energy efficient cooperative Diversity Scheme based on quadrature signaling is proposed. The quadrature signaling is achieved by transmitting in the in-phase and quadrature components of QPSK modulation. The Diversity gain and the bit error rate of the proposed cooperative Diversity Scheme improve with the inter-user channel quality. It is shown that the proposed Scheme can achieve a Diversity order of two for high inter-user signal-to-noise ratios, if the cooperating users are located within a region that permits successful cooperation. The cooperative region corresponding to a specified bit error rate is defined and derived

  • a simple cooperative Diversity Scheme based on orthogonal signaling mobile radio applications
    Wireless Communications and Networking Conference, 2005
    Co-Authors: V Mahinthan, Jon W Mark
    Abstract:

    In this paper, a bandwidth efficient and energy efficient cooperative Diversity Scheme is proposed based on orthogonal signaling. Orthogonal signaling is achieved by transmitting in the in-phase and quadrature components of a phase shift keying modulation system. The bit error rate performance of the proposed cooperative Diversity Scheme increases with interuser signal strength. Numerical results show that the proposed cooperative Diversity Scheme can achieve the Diversity order of two for high interuser signal-to-noise ratio.