Minimum PER user-energy profile for massive SIC receivers under an average energy constraint

Abstract

Interference may pose a severe limitation to massive wireless multiple access unless the central receiver is endowed with strong multipacket reception capabilities. In that respect, Interference Cancellation (IC) has been extensively studied [1]–[3]. Such systems have been proposed for satellite communications, combining Direct Sequence (DS) Code Division Multiple Access (CDMA) with a SIC receiver [4]–[6] or using multipacket transmission as in Contention Resolution Diversity Slotted ALOHA (CRDSA) [7] [8]. The use of powerful encoders coupled with power imbalance at reception favours IC and has considerably improved the throughput of such random access protocols [4] [9]. In a context characterized by high user activity and spectrum/orbit congestion [10], it is of interest to develop schemes for space assets that optimize the aggregate spectral efficiency of the user population.Peer ReviewedPostprint (published version

Optimal Power Control Law for Equal-Rate DS-CDMA Networks Governed by a Successive Soft Interference Cancellation Scheme

“…With respect to (i), this work has obtained the true RE vs. SINR curve of the iterative FEC decoder, rather than utilized the non-informative uniform (SINR-independent) assumption in previous works. We evidence that the adopted soft SIC decoding policy and the associated VC-based optimization procedure outperform the previously used strategies [10] [11].…”

“…We consider a very large population of 1  k  K low-rate users transmitting towards a satellite repeater, in which the user index is established in decreasing order of the user channel power gains h [k]. For an affordable theoretical analysis, we have evaluated the synchronous access mode implemented in some standards [4] and also analyzed in [10][11] [12]. At the physical layer, the same coding and modulation scheme is considered for all users, in which symbol sequences s k [n] are generated.…”

“…Enhanced Spread Spectrum Aloha, a system employing coded Direct-Sequence (DS) Code-Division-Multiple-Access together with SIC at reception [6] [7], has been proposed as a powerful solution with an affordable implementation complexity [8] [9]. Previous works have addressed network throughput optimization in the large-user regime under specific hard SIC policies [10] [11]. In the machine-to-machine context, characterized Work supported by projects TEC2016-76409-C2-1-R (WINTER) and TEC2013-47020-C2-2-R (COMPASS): Ministerio de Economía, Industria y Competitividad.…”

“…We recover the scenario in [10], where a satellite operating as a relay between a large population network and a gateway station is envisaged. In that context, the first contribution of this paper is the hitherto unexplored VC-based optimization of the system's spectral efficiency when a soft SIC (rather than a hard SIC [10]) operates at the gateway.…”

“…We recover the scenario in [10], where a satellite operating as a relay between a large population network and a gateway station is envisaged. In that context, the first contribution of this paper is the hitherto unexplored VC-based optimization of the system's spectral efficiency when a soft SIC (rather than a hard SIC [10]) operates at the gateway. Specifically, we derive the optimum power control law of a massive spread-spectrum multiple access network under synchronous access when: (i) users share the same practical encoding and modulation scheme, associated with a known PER vs. SINR curve, as well as a known RE vs. SINR curve corresponding to the soft cancellation procedure; (ii) the satellite repeater sets a sum power constraint over the user population.…”