This paper proposes a hybrid wireless communication framework that integrates an active intelligent reflecting surface(IRS)with a decode-andforward(DF)relay to enhance spectral efficiency in extended-range scenarios.B...This paper proposes a hybrid wireless communication framework that integrates an active intelligent reflecting surface(IRS)with a decode-andforward(DF)relay to enhance spectral efficiency in extended-range scenarios.By combining the amplification capability of the active IRS and the signal regeneration function of the DF relay,the proposed system effectively mitigates path loss and fading.We derive closed-form upper bounds on the achievable rate and develop an optimal power allocation strategy under a total power constraint.Numerical results demonstrate that the hybrid scheme significantly outperforms conventional passive IRS-assisted or active IRS-only configurations,particularly under conditions of limited reflecting elements or moderate signal-to-noise ratios.展开更多
A terrestrial relay-aided reconfigurable intelligent surface(RIS)system with decode,re-encode and forward(DRF)relaying scheme is presented where the RIS effectively contributes to both sourceto-destination and relay-t...A terrestrial relay-aided reconfigurable intelligent surface(RIS)system with decode,re-encode and forward(DRF)relaying scheme is presented where the RIS effectively contributes to both sourceto-destination and relay-to-destination signaling.While in the conventional decode and forward(DF)relaying scheme,the source signal is merely duplicated in the relay and the time intervals are equally allocated to the source and relay nodes,this paper considers DRF relaying scheme where versatile time-sharing is adopted for the source and relay nodes which can be optimized based on the relative coordinates of the involved nodes.Two protocols namely unidirectional connection(UC)and bidirectional connection(BC)are proposed based on the source awareness from the relay’s successful reception.The outage probability(OP)performance for both protocols and both DF and DRF relaying schemes is analyzed and tight approximations are obtained.The numerical results show the out-performance of the DRF over the DF relaying scheme in the both UC and BC protocols.Equipped with the obtained system OP,the system throughput is defined and the optimum system throughput is obtained by optimizing the system rate and the timesharing between the source and the relay.Analytical results are corroborated in the numerical examples.展开更多
This paper proposes rate-maximized （MR） joint subcarrier pairing （SP） and power allocation （PA） （MR-SP＆PA）, a novel scheme for maximizing the weighted sum rate of the orthogonal-frequency-division multiplexi...This paper proposes rate-maximized （MR） joint subcarrier pairing （SP） and power allocation （PA） （MR-SP＆PA）, a novel scheme for maximizing the weighted sum rate of the orthogonal-frequency-division multiplexing （OFDM） relaying system with a decode-and-forward （DF） relay. MR-SP＆PA is based on the joint optimization of both SP and power allocation with total power constraint, and formulated as a mixed integer programming problem in the paper. The programming problem is then transformed to a convex optimization problem by using continuous relaxation, and solved in the Lagrangian dual domain. Simulation results show that MR-SP＆PA can maximize the weighted sum rate under total power constraint and outperform equal power allocation （EPA） and proportion power allocation （PCG）.展开更多
In this paper, we consider the power optimization problem in Orthogonal Frequency Division Multiplexing （OFDM）-based relay-enhanced device-to-device （D2D） communication. In a single cell transmission scenario, dua...In this paper, we consider the power optimization problem in Orthogonal Frequency Division Multiplexing （OFDM）-based relay-enhanced device-to-device （D2D） communication. In a single cell transmission scenario, dual- hop communication is assumed in which each D2D user re-uses the spectrum of just one Cellular User （CU）. In this work, we formulate a joint optimization scheme under a Decode-and-Forward （DF） relaying protocol to maximize the sum throughput of D2D and cellular networks via power allocation over different sub-carriers. The problem is thus transformed into a standard convex optimization, subject to individual power constraints at different transmitting nodes. We exploit the duality theory to decompose the problem into several sub-problems and use Karush-Kuhn- Tucker （KKT） conditions to solve each sub-problem. We provide simulation results to validate the performance of our proposed scheme.展开更多
基金supported in part by National Key R&D Program of China(2022YFB2903500)NSFC Grant 62331022,Grant 62371289+4 种基金Grant 624B2094in part by the Shanghai Jiao Tong University 2030 Initiative,and the Guangdong Science and Technology program under grant 2022A0505050011in part by the Outstanding Doctoral Graduates Development Scholarship of Shanghai Jiao Tong Universityin part by Shanghai Kewei under Grant 22JC1404000Grant 24DP1500500.
文摘This paper proposes a hybrid wireless communication framework that integrates an active intelligent reflecting surface(IRS)with a decode-andforward(DF)relay to enhance spectral efficiency in extended-range scenarios.By combining the amplification capability of the active IRS and the signal regeneration function of the DF relay,the proposed system effectively mitigates path loss and fading.We derive closed-form upper bounds on the achievable rate and develop an optimal power allocation strategy under a total power constraint.Numerical results demonstrate that the hybrid scheme significantly outperforms conventional passive IRS-assisted or active IRS-only configurations,particularly under conditions of limited reflecting elements or moderate signal-to-noise ratios.
文摘A terrestrial relay-aided reconfigurable intelligent surface(RIS)system with decode,re-encode and forward(DRF)relaying scheme is presented where the RIS effectively contributes to both sourceto-destination and relay-to-destination signaling.While in the conventional decode and forward(DF)relaying scheme,the source signal is merely duplicated in the relay and the time intervals are equally allocated to the source and relay nodes,this paper considers DRF relaying scheme where versatile time-sharing is adopted for the source and relay nodes which can be optimized based on the relative coordinates of the involved nodes.Two protocols namely unidirectional connection(UC)and bidirectional connection(BC)are proposed based on the source awareness from the relay’s successful reception.The outage probability(OP)performance for both protocols and both DF and DRF relaying schemes is analyzed and tight approximations are obtained.The numerical results show the out-performance of the DRF over the DF relaying scheme in the both UC and BC protocols.Equipped with the obtained system OP,the system throughput is defined and the optimum system throughput is obtained by optimizing the system rate and the timesharing between the source and the relay.Analytical results are corroborated in the numerical examples.
基金supported by the National Key Technology R&D Program (2008BAH30B10)the National Natural Science Foundation of China (60972070)+1 种基金the Chongqing Municipal Science & Technology Development Program,China (CSTC2010A-C2143)the Natural Science Foundation of Chongqing,China (CSTC2009B-A2090)
文摘This paper proposes rate-maximized （MR） joint subcarrier pairing （SP） and power allocation （PA） （MR-SP＆PA）, a novel scheme for maximizing the weighted sum rate of the orthogonal-frequency-division multiplexing （OFDM） relaying system with a decode-and-forward （DF） relay. MR-SP＆PA is based on the joint optimization of both SP and power allocation with total power constraint, and formulated as a mixed integer programming problem in the paper. The programming problem is then transformed to a convex optimization problem by using continuous relaxation, and solved in the Lagrangian dual domain. Simulation results show that MR-SP＆PA can maximize the weighted sum rate under total power constraint and outperform equal power allocation （EPA） and proportion power allocation （PCG）.
文摘In this paper, we consider the power optimization problem in Orthogonal Frequency Division Multiplexing （OFDM）-based relay-enhanced device-to-device （D2D） communication. In a single cell transmission scenario, dual- hop communication is assumed in which each D2D user re-uses the spectrum of just one Cellular User （CU）. In this work, we formulate a joint optimization scheme under a Decode-and-Forward （DF） relaying protocol to maximize the sum throughput of D2D and cellular networks via power allocation over different sub-carriers. The problem is thus transformed into a standard convex optimization, subject to individual power constraints at different transmitting nodes. We exploit the duality theory to decompose the problem into several sub-problems and use Karush-Kuhn- Tucker （KKT） conditions to solve each sub-problem. We provide simulation results to validate the performance of our proposed scheme.
