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Constellation Constrained (CC) capacity regions of two-user Single-Input Single-Output (SISO) Gaussian Multiple Access Channels (GMAC) are computed for several Non-Orthogonal Multiple Access schemes (NO-MA) and Orthogonal Multiple Access schemes (O-MA). For NO-MA schemes, a metric is proposed to compute the angle(s) of rotation between the input(More)
The capacity region of a two-user Gaussian multiple access channel (GMAC) with complex finite input alphabets and continuous output alphabet is studied. When both the users are equipped with the same code alphabet, it is shown that, rotation of one of the userpsilas alphabets by an appropriate angle can make the new pair of alphabets not only uniquely(More)
Distributed orthogonal space-time block codes (DOSTBCs) achieving full-diversity order and single-symbol maximum-likelihood (ML) decodability have been introduced recently by Yi and Kim for cooperative networks, and an upper bound on the maximal rate of such codes along with code constructions has been presented. In this paper, a new class of single-symbol(More)
— Distributed space time coding for wireless relay networks where the source, the destination and the relays have multiple antennas have been studied by Jing and Hassibi. In this set up, the transmit and the receive signals at different antennas of the same relay are processed and designed independently, even though the antennas are colocated. In this(More)
Constellation Constrained (CC) capacity regions of a two-user Gaussian Multiple Access Channel (GMAC) have been recently reported. For such a channel, code pairs based on trellis coded modulation are proposed in this paper with M-PSK and M-PAM alphabet pairs, for arbitrary values of M; to achieve sum rates close to the CC sum capacity of the GMAC. In(More)
— Constellation Constrained (CC) capacity regions of two-user Gaussian Multiple Access Channels (GMAC) have been recently reported, wherein an appropriate angle of rotation between the constellations of the two users is shown to enlarge the CC capacity region. We refer to such a scheme as the Constellation Rotation (CR) scheme. In this paper, we propose a(More)
— Constellation Constrained (CC) capacity regions of a two-user SISO Gaussian Multiple Access Channel (GMAC) with finite complex input alphabets and continuous output are computed in this paper. When both the users employ the same code alphabet, it is well known that an appropriate rotation between the alphabets provides unique decodability to the receiver.(More)
— Recently, the idea of space-time coding has been applied to wireless relay networks wherein a set of geographically separated relay nodes cooperate to process the received signal from the source and forward them to the destination such that the signal received at the destination appears like a Space-Time Block Code (STBC). Such STBCs (referred to as(More)
— Distributed Space-Time Block Codes (DSTBCs) from Complex Orthogonal Designs (CODs) (both square and non-square CODs other than the Alamouti design) are known to lose their single-symbol ML decodable (SSD) property when used in two-hop wireless relay networks using amplify and forward protocol. For such a network, in this paper, a new class of high rate,(More)
fading MAC such that the sphere decoding complexity is reduced. I. INTRODUCTION AND PRELIMINARIES Capacity regions of two-user Gaussian Multiple Access Channels (GMAC) (shown in Fig.1) are well known in the literature wherein the capacity achieving input is continuous and Gaussian distributed [1]-[5]. Though, capacity regions of such channels provide(More)