160 research outputs found
PERFORMANCE OF UPLINK-NOMA WITH USER PAIRING AND DATA RATE-BASED POWER SCHEME
This paper analyzes a performance of uplink power-domain non-orthogonal multiple access (NOMA) system with 2K users in which a resource allocation is taken into consideration. Since the power allocation and user pairing are tightly intertwined, they are considered as a hybrid issue. Accordingly, High-High/High-Low user pairing process precedes date rate-based power allocation. Derived closed-form expressions for the outage probabilities and the sum data rate for uplink power-domain NOMA system over a composite Fisher-Snedecor (F) fading channel are used for an extensive performance evaluation. The impact of different fading/shadowing channel conditions, various users’ positions and their number on the performance metrics is examined. Presented results have high level of generality since the F fading model provides accurate characterization of the multipath/shadowing conditions in numerous communication scenarios of interest
A NOMA-enhanced reconfigurable access scheme with device pairing for M2M networks
This paper aims to address the distinct requirements
of machine-to-machine networks, particularly heterogeneity and
massive transmissions. To this end, a reconfigurable medium
access control (MAC) with the ability to choose a proper access
scheme with the optimal configuration for devices based on
the network status is proposed. In this scheme, in each frame,
a separate time duration is allocated for each of the nonorthogonal multiple access (NOMA)-based, orthogonal multiple
access (OMA)-based, and random access-based segments, where
the length of each segment can be optimized. To solve this
optimization problem, an iterative algorithm consisting of two
sub-problems is proposed. The first sub-problem deals with
selecting devices for the NOMA/OMA-based transmissions, while
the second one optimizes the parameter of the random access
scheme. To show the efficacy of the proposed scheme, the results
are compared with the reconfigurable scheme which does not
support NOMA. The results demonstrate that by using a proper
device pairing scheme for the NOMA-based transmissions, the
proposed reconfigurable scheme achieves better performance
when NOMA is adopted
NON-ORTHOGONAL MULTIPLE ACCESS: A COMPREHENSIVE ANALYTICAL STUDY AND OPTIMISATION IN FADING CHANNELS
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