On the Performance of Alamouti-Coded Cooperative NOMA with Imperfect Channel State Information

• As the number of mobile devices grows exponentially, it is critical to design a robust access scheme that can handle a large number of devices with low latency. Non-orthogonal multiple access (NOMA) is an effective approach to meet such requirements that can provide higher spectral efficiency. As an extended version, cooperative NOMA has been introduced, where the users with higher channel gains forward signals for users with weak channel gains as cooperators. The conventional cooperative NOMA (CCN) technique can provide diversity gains, which can be used to improve reliability. However, in CCN, the overhead caused by successive interference cancellations (SIC) at each user may become significant, when there exist a massive number of users, which eventually degrades the performance of NOMA considering the power and computational resource limitations of mobile devices. As an alternative, the space-time block-coded NOMA (STBC-NOMA) has been proposed to achieve diversity gain with lower SIC overhead compared to CCN. To better evaluate it, in this paper, we investigate the impact of imperfect channel state information (ipCSI), which is more realistic in real-time processing. We dervie the closed-form expression of the outage probability of STBC-NOMA with ipCSI and compare its performance with CCN and conventional NOMA. © 2021 IEEE.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik -- Kommunikationssystem (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering -- Communication Systems (hsv//eng)

Nyckelord

cooperative NOMA

imperfect channel

NOMA

outage probability

SIC

STBC

Space time codes

Space-time block coding (STBC)

Closed-form expression

Computational resources

Effective approaches

Imperfect channel state information

Realtime processing

Space-time block coded

Spectral efficiencies

Successive interference cancellation(SIC)

Channel state information

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