A CDMA mixed cellular architecture with space division duplex (SDD) for symmetric/asymmetric wireless communications

Abstract

We explore the use of a novel duplex scheme -Space Division Duplex (SDD) in a CDMA mixed cellular architecture for supporting symmetric data services and asymmetric data services with the former served by FDD regular cells and the latter served by SDD picocells (System I). Using per-cell capacity as our measure, the performance of System I is evaluated and compared with two other approaches (System I1 and 111) in which System I1 utilizes FDD in both regular cells and picocells and System I11 simply utilizes FDD in a regular cellular architecture to serve both symmetric and asymmetric data users.

Beamforming for Space Division Duplexing

“…Hence, we focus only on 'Transmit SDD' and 'Receive SDD'. 1 Reference [10] examines another possibility based on the orthogonality of eigenvectors. It holds if numbers of transmit and receive antennas are equal.…”

“…Spectral efficiency being based on the resource utilization in time-and frequency-dimensions, the use of other independent dimensions to achieve duplexing has become attractive, despite the practical challenges. Space division duplexing (SDD) for single-antenna systems has been attempted [1], [2] in this respect, however, with non-spatial techniques for interference suppression. It is with multiple-input multiple-output (MIMO) technology, which supports system nodes with multiple spatial DoFs, that spatial interference suppression became possible.…”

Resource allocation in multihop cellular networks

“…As a last remark on duplexing techniques, Space-Division Duplexing (SDD) was also proposed and it should be used with smart directional antennas in the future generation cellular systems [39].…”