TY - JOUR
T1 - Non-Orthogonal Unicast and Broadcast Transmission via Joint Beamforming and LDM in Cellular Networks
AU - Zhao, Junlin
AU - Gündüz, Deniz
AU - Simeone, Osvaldo
AU - Gómez-Barquero, David
N1 - Funding Information:
Manuscript received April 1, 2019; accepted May 22, 2019. Date of publication August 14, 2019; date of current version June 5, 2020. The work of J. Zhao and D. Gündüz was supported in part by the European Research Council through Project BEACON under Grant 677854, and in part by the European Unions Horizon 2020 Research and Innovation Programme through Project SCAVENGE under Grant 675891. The work of O. Simeone was supported by the European Research Council through the European Union Horizon 2020 Research and Innovation Program under Grant 725731. Part of this work was presented at the IEEE Global Communications Conference (Globecom), Washington, DC, USA, Dec. 2016 [1]. (Corresponding author: Junlin Zhao.) J. Zhao and D. Gündüz are with the Department of Electrical and Electronic Engineering, Imperial College London, London SW7 2BT, U.K. (e-mail: j.zhao15@imperial.ac.uk; d.gunduz@imperial.ac.uk).
Publisher Copyright:
© 1963-12012 IEEE.
PY - 2020/6
Y1 - 2020/6
N2 - Limited bandwidth resources and higher energy efficiency requirements motivate incorporating multicast and broadcast transmission into the next-generation cellular network architectures, particularly for multimedia streaming applications. Layered division multiplexing (LDM), a form of non-orthogonal multiple access (NOMA), can potentially improve unicast throughput and broadcast coverage with respect to traditional orthogonal frequency division multiplexing (FDM) or time division multiplexing (TDM), by simultaneously using the same frequency and time resources for multiple unicast or broadcast transmissions. In this paper, the performance of LDM-based unicast and broadcast transmission in a cellular network is studied by assuming a single frequency network (SFN) operation for the broadcast layer, while allowing arbitrarily clustered cooperation among the base stations (BSs) for the transmission of unicast data streams. Beamforming and power allocation between unicast and broadcast layers, the so-called injection level in the LDM literature, are optimized with the aim of minimizing the sum-power under constraints on the user-specific unicast rates and on the common broadcast rate. The effects of imperfect channel coding and imperfect channel state information (CSI) are also studied to gain insights into robust implementation in practical systems. The non-convex optimization problem is tackled by means of successive convex approximation (SCA) techniques. Performance upper bounds are also presented by means of the S-procedure followed by semidefinite relaxation (SDR). Finally, a dual decomposition-based solution is proposed to facilitate an efficient distributed implementation of LDM in each of the SCA subproblems, where the unicast beamforming vectors can be obtained locally by the cooperating BSs. Numerical results are presented, which show the tightness of the proposed bounds and hence the near-optimality of the proposed solutions.
AB - Limited bandwidth resources and higher energy efficiency requirements motivate incorporating multicast and broadcast transmission into the next-generation cellular network architectures, particularly for multimedia streaming applications. Layered division multiplexing (LDM), a form of non-orthogonal multiple access (NOMA), can potentially improve unicast throughput and broadcast coverage with respect to traditional orthogonal frequency division multiplexing (FDM) or time division multiplexing (TDM), by simultaneously using the same frequency and time resources for multiple unicast or broadcast transmissions. In this paper, the performance of LDM-based unicast and broadcast transmission in a cellular network is studied by assuming a single frequency network (SFN) operation for the broadcast layer, while allowing arbitrarily clustered cooperation among the base stations (BSs) for the transmission of unicast data streams. Beamforming and power allocation between unicast and broadcast layers, the so-called injection level in the LDM literature, are optimized with the aim of minimizing the sum-power under constraints on the user-specific unicast rates and on the common broadcast rate. The effects of imperfect channel coding and imperfect channel state information (CSI) are also studied to gain insights into robust implementation in practical systems. The non-convex optimization problem is tackled by means of successive convex approximation (SCA) techniques. Performance upper bounds are also presented by means of the S-procedure followed by semidefinite relaxation (SDR). Finally, a dual decomposition-based solution is proposed to facilitate an efficient distributed implementation of LDM in each of the SCA subproblems, where the unicast beamforming vectors can be obtained locally by the cooperating BSs. Numerical results are presented, which show the tightness of the proposed bounds and hence the near-optimality of the proposed solutions.
KW - Digital multimedia broadcasting
KW - MISO
KW - multiplexing
KW - non-orthogonal multiple access
KW - optimization
KW - wireless networks
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U2 - 10.1109/TBC.2019.2932339
DO - 10.1109/TBC.2019.2932339
M3 - Article
AN - SCOPUS:85086315740
SN - 0018-9316
VL - 66
SP - 216
EP - 228
JO - IRE Transactions on Broadcasting
JF - IRE Transactions on Broadcasting
IS - 2
M1 - 8798992
ER -