Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 4 of 4
Full-Text Articles in Engineering
Optimal Training Sequences For Joint Timing Synchronization And Channel Estimation In Distributed Communication Networks, Ali A. Nasir, Hani Mehrpouyan, Salman Durrani, Steven D. Blostein, Rodney A. Kennedy, Björn Ottersten
Optimal Training Sequences For Joint Timing Synchronization And Channel Estimation In Distributed Communication Networks, Ali A. Nasir, Hani Mehrpouyan, Salman Durrani, Steven D. Blostein, Rodney A. Kennedy, Björn Ottersten
Hani Mehrpouyan
For distributed multi-user and multi-relay cooperative networks, the received signal may be affected by multiple timing offsets (MTOs) and multiple channels that need to be jointly estimated for successful decoding at the receiver. This paper addresses the design of optimal training sequences for efficient estimation of MTOs and multiple channel parameters. A new hybrid Cramér-Rao lower bound (HCRB) for joint estimation of MTOs and channels is derived. Subsequently, by minimizing the derived HCRB as a function of training sequences, three training sequence design guidelines are derived and according to these guidelines, two training sequences are proposed. In order to show …
Simultaneous Estimation Of Multi-Relay Mimo Channels, Hani Mehrpouyan, Steven D. Blostein, Björn Ottersten
Simultaneous Estimation Of Multi-Relay Mimo Channels, Hani Mehrpouyan, Steven D. Blostein, Björn Ottersten
Hani Mehrpouyan
This paper addresses training-based channel estimation in distributed amplify-and-forward (AF) multi-input multi-output (MIMO) multi-relay networks. To reduce channel estimation overhead and delay, a training algorithm that allows for simultaneous estimation of the entire MIMO cooperative network’s channel parameters at the destination node is proposed. The exact Cramér-Rao lower bound (CRLB) for the problem is presented in closed-form. Channel estimators that are capable of estimating the overall source-relay-destination channel parameters at the destination are also derived. Numerical results show that while reducing delay, the proposed channel estimators are close to the derived CRLB over a wide range of signal-to-noise ratio values …
New Expression For The Functional Transformation Of The Vector Cramér-Rao Lower Bound, Ali A. Nasir, Hani Mehrpouyan, Rodney A. Kennedy
New Expression For The Functional Transformation Of The Vector Cramér-Rao Lower Bound, Ali A. Nasir, Hani Mehrpouyan, Rodney A. Kennedy
Hani Mehrpouyan
Assume that it is desired to estimate α = f(θ), where f(·) is an r-dimensional function. This paper derives the general expression for the functional transformation of the vector Cramér-Rao lower bound (CRLB). The derived bound is a tight lower bound on the estimation of uncoupled parameters, i.e., parameters that can be estimated separately. Unlike previous results in the literature, this new expression is not dependent on the inverse of the Fisher’s information matrix (FIM) of the untransformed parameters, θ. Thus, it can be applied to scenarios where the FIM for θ is ill-conditioned or singular. …
Dstbc Based Df Cooperative Networks In The Presence Of Timing And Frequency Offsets, Ali A. Nasir, Hani Mehrpouyan, Salman Durrani, Steven D. Blostein, Rodney A. Kennedy, Björn Ottersten
Dstbc Based Df Cooperative Networks In The Presence Of Timing And Frequency Offsets, Ali A. Nasir, Hani Mehrpouyan, Salman Durrani, Steven D. Blostein, Rodney A. Kennedy, Björn Ottersten
Hani Mehrpouyan
In decode-and-forward (DF) relaying networks, the received signal at the destination may be affected by multiple impairments such as multiple channel gains, multiple timing offsets (MTOs), and multiple carrier frequency offsets (MCFOs). This paper proposes novel optimal and sub-optimal minimum mean-square error (MMSE) receiver designs at the destination node to detect the signal in the presence of these impairments. Distributed space-time block codes (DSTBCs) are used at the relays to achieve spatial diversity. The proposed sub-optimal receiver uses the estimated values of multiple channel gains, MTOs, and MCFOs, while the optimal receiver assumes perfect knowledge of these impairments at the …