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Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Optimizing Computation Efficiency for NOMA-Assisted Mobile Edge Computing with User Cooperation
AU - Su, B.
AU - Ni, Q.
AU - Yu, W.
AU - Pervaiz, H.
N1 - ©2021 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
PY - 2021/6/30
Y1 - 2021/6/30
N2 - In this paper, we investigate the application of user cooperation (UC) and non-orthogonal multiple access (NOMA) schemes for a wireless powered mobile edge computing (MEC) system under the non-linear energy harvesting model, in which two single-antenna mobile users first harvest energy from a multi-antenna access point (AP) integrated with an MEC server. Then, during the computation offloading phase, both mobile users simultaneously offload tasks to the MEC server with the harvested energy, by performing NOMA protocol. To better enhance the system performance, UC scheme is carried out, where the near user acts as a relay to help the far user offload computation tasks to the AP. To obtain energy efficient MEC design, our objective is to maximize the computation efficiency (i.e., the total computation bits divided by the consumed energy) by jointly designing the energy beamforming, time and power allocations, which yields a challenging nonconvex optimization problem. To deal with it, the original problem is first transformed into a more tractable formulation by applying the semidefinite relaxation (SDR) technique and then solved by utilizing the sequential convex approximation (SCA) method. Numerical results demonstrate that UC has a great impact when two users are close, while NOMA makes effect when two users are relatively far. Combining both NOMA and UC, the proposed scheme, named NOMA-UC MEC, yields better system performance than the benchmark schemes.
AB - In this paper, we investigate the application of user cooperation (UC) and non-orthogonal multiple access (NOMA) schemes for a wireless powered mobile edge computing (MEC) system under the non-linear energy harvesting model, in which two single-antenna mobile users first harvest energy from a multi-antenna access point (AP) integrated with an MEC server. Then, during the computation offloading phase, both mobile users simultaneously offload tasks to the MEC server with the harvested energy, by performing NOMA protocol. To better enhance the system performance, UC scheme is carried out, where the near user acts as a relay to help the far user offload computation tasks to the AP. To obtain energy efficient MEC design, our objective is to maximize the computation efficiency (i.e., the total computation bits divided by the consumed energy) by jointly designing the energy beamforming, time and power allocations, which yields a challenging nonconvex optimization problem. To deal with it, the original problem is first transformed into a more tractable formulation by applying the semidefinite relaxation (SDR) technique and then solved by utilizing the sequential convex approximation (SCA) method. Numerical results demonstrate that UC has a great impact when two users are close, while NOMA makes effect when two users are relatively far. Combining both NOMA and UC, the proposed scheme, named NOMA-UC MEC, yields better system performance than the benchmark schemes.
KW - computation efficiency.
KW - Energy harvesting
KW - Mobile edge computing
KW - NOMA
KW - non-orthogonal multiple access
KW - Resource management
KW - Servers
KW - Task analysis
KW - Uplink
KW - user cooperation
KW - Wireless communication
KW - wireless powered
KW - Benchmarking
KW - Edge computing
KW - Energy efficiency
KW - Rectennas
KW - Computation efficiency
KW - Computation offloading
KW - Computation tasks
KW - Convex approximation
KW - Nonconvex optimization problem
KW - Numerical results
KW - Semidefinite relaxation
KW - Time and power allocations
KW - Computational efficiency
U2 - 10.1109/TGCN.2021.3056770
DO - 10.1109/TGCN.2021.3056770
M3 - Journal article
VL - 5
SP - 858
EP - 867
JO - IEEE Transactions on Green Communications and Networking
JF - IEEE Transactions on Green Communications and Networking
SN - 2473-2400
IS - 2
ER -