Abstract
The combination of simultaneous wireless information
and power transfer (SWIPT) and non-orthogonal multiple
access (NOMA) is a potential solution to improve spectral
efficiency (SE) and energy efficiency (EE) of the upcoming fifth
generation (5G) networks, especially in order to support the
functionality of the Internet of things (IoT) and the massive
machine-type communications (mMTC) scenarios. In this paper,
we investigate joint power allocation and time switching (TS)
control for EE optimization in a TS-based SWIPT NOMA
system. Our aim is to optimize the EE of the system whilst
satisfying the constraints on maximum transmit power budget,
minimum data rate and minimum harvested energy per-terminal.
The considered EE optimization problem is neither linear nor
convex involving joint optimization of power allocation and time
switching factors, and thus is extremely difficult to solve directly.
In order to tackle this problem, we develop a dual-layer algorithm
where Dinkelbach method is employed both in the inner-layer to
optimize the power allocation and in the outer-layer to control
the time switching assignment. Furthermore, a simplified but
practical special case with equal time switching factors in all
terminals is considered. Numerical results validate the theoretical
findings and demonstrate that significant performance gain over
orthogonal multiple access (OMA) scheme in terms of EE can be
achieved by the proposed algorithms in a SWIPT-enabled NOMA
system.
and power transfer (SWIPT) and non-orthogonal multiple
access (NOMA) is a potential solution to improve spectral
efficiency (SE) and energy efficiency (EE) of the upcoming fifth
generation (5G) networks, especially in order to support the
functionality of the Internet of things (IoT) and the massive
machine-type communications (mMTC) scenarios. In this paper,
we investigate joint power allocation and time switching (TS)
control for EE optimization in a TS-based SWIPT NOMA
system. Our aim is to optimize the EE of the system whilst
satisfying the constraints on maximum transmit power budget,
minimum data rate and minimum harvested energy per-terminal.
The considered EE optimization problem is neither linear nor
convex involving joint optimization of power allocation and time
switching factors, and thus is extremely difficult to solve directly.
In order to tackle this problem, we develop a dual-layer algorithm
where Dinkelbach method is employed both in the inner-layer to
optimize the power allocation and in the outer-layer to control
the time switching assignment. Furthermore, a simplified but
practical special case with equal time switching factors in all
terminals is considered. Numerical results validate the theoretical
findings and demonstrate that significant performance gain over
orthogonal multiple access (OMA) scheme in terms of EE can be
achieved by the proposed algorithms in a SWIPT-enabled NOMA
system.
| Original language | English |
|---|---|
| Pages (from-to) | 452-466 |
| Journal | IEEE Journal of Selected Topics in Signal Processing |
| Volume | 13 |
| Issue number | 3 |
| Early online date | 7 Feb 2019 |
| DOIs | |
| Publication status | Published - 7 Feb 2019 |
Keywords
- simultaneous wireless information and power transfer (SWIPT)
- Energy efficiency (EE)
- non-orthogonal multiple access (NOMA)
- time switching (TS)
