We consider the multi-user MIMO broadcast channel with M single-antenna users and N transmit antennas under the constraint that each antenna emits signals having constant envelope (CE). The motivation for this is that CE signals facilitate the use of power-efficient RF power amplifiers. Analytical and numerical results show that, under certain mild conditions on the channel gains, for a fixed M, an array gain is achievable even under the stringent per-antenna CE constraint. Essentially, for a fixed M, at sufficiently large N the total transmitted power can be reduced with increasing N while maintaining a fixed information rate to each user. Simulations for the i.i.d. Rayleigh fading channel show that the total transmit power can be reduced linearly with increasing N (i.e., an O(N) array gain). We also propose a precoding scheme which finds near-optimal CE signals to be transmitted, and has O(MN) complexity. Also, in terms of the total transmit power required to achieve a fixed desired information sum-rate, despite the stringent per-antenna CE constraint, the proposed CE precoding scheme performs close to the sum-capacity achieving scheme for an average-only total transmit power constrained channel. / <p>Funding Agencies|Swedish Foundation for Strategic Research (SSF)||ELLIIT||Knut and Alice Wallenberg Foundation||Center for Industrial Information Technology at ISY, Linkoping University (CENIIT)||</p>
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:liu-93866 |
| Date | January 2013 |
| Creators | Khan Mohammed, Saif, Larsson, Erik G. |
| Publisher | Linköpings universitet, Institutionen för systemteknik, Linköpings universitet, Tekniska högskolan, Linköpings universitet, Kommunikationssystem, Linköpings universitet, Tekniska högskolan, Institute of Electrical and Electronics Engineers (IEEE) |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Article in journal, info:eu-repo/semantics/article, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | IEEE Transactions on Communications, 0090-6778, 2013, 61:3, s. 1059-1071 |
Page generated in 0.0014 seconds