On degrees-of-freedom of multi-user MIMO full-duplex network

Abstract

When a multi-antenna (MIMO) base-station operates in full-duplex mode, multiple uplink and downlink streams can be supported simultaneously in the same frequency band. However, the inter-mobile interference from uplink streams to the downlink streams can limit the system performance. In this paper, we first characterize the degrees-of-freedom of a multiuser MIMO (MU-MIMO) full-duplex network with half-duplex mobile clients, and derive the regimes where the inter-mobile interference can be mitigated to yield significant gains over the half-duplex counterpart. The achievability is based on interference alignment and requires full channel-state information at the transmitter (CSIT). Next, we study the case with partial CSIT where only the base-station acquires downlink channel values to avoid collecting network-wide CSIT at all transmitters in the system. We show that the key to achieving the sum degrees-offreedom upper bound with only partial CSIT is the ability of the base-station to switch antenna modes that can be realized via reconfigurable antennas.

Degrees of Freedom of Full-Duplex Cellular Networks With Reconfigurable Antennas at Base Station

“…The result shows that the sum DoF is doubled if there exist two DL and two UL users and two preset modes at the transmitter and the receiver of the BS. For the single-antenna case, our result for the partial CSIT model extends the previous achievability result in [13] to a general antenna configuration assuming different numbers of preset modes at the transmitter and receiver of the BS. • We further demonstrate that such DoF improvement indeed yields the sum rate improvement at the finite and operational signal-to-noise ratio (SNR) regime, which presents the benefit of blind IA using reconfigurable antennas compared with the previous works [10]- [13].…”

“…In order to understand fundamental limits of FD radios in cellular networks, there have been several recent researches on characterizing the degrees of freedom (DoF) of FD cellular networks [10]- [13]. In particular, a single-cell FD cellular network has been studied in [12], [13], in which a FD BS with perfect self-interference suppression supports both HD DL and UL users FD BS User-to-user interference as seen in Fig. 1.…”

“…For both models, we assume that CSI at the receive side (CSIR) is available. Similar to the previous full CSIT models in [10]- [13], the primary aim is to characterize whether the sum DoF can be doubled or not with partial or no CSIT by FD operation at the BS equipped with reconfigurable antennas. The main contributions of this paper are as follows:…”

Fundamental Limits of Spectrum Sharing Full-Duplex Multicell Networks

“…However, it can be easily checked that the upper bound (8) in Theorem 3 is tighter than (11) for all values of K, M , and N . ♦ Remark 4 (Optimality condition): As mentioned in Remark 2, d Σ has been characterized for the single-cell case [35], [38] . Hence, focus on the multi-cell case where K ≥ 2.…”

Asymptotic Analysis of MIMO Multi-Cell Full-Duplex Networks

“…The first line of work focuses on information theoretic limits while the other line of work focuses on practical network design. Towards that end, we discuss [15][16][17][18][19][20][21][22][23]; note that not all papers are multi-cell studies. In [15][16][17][18][19], only a single-cell MIMO full-duplex case is studied.…”