2 research outputs found
Throughput Analysis and Energy Efficiency Optimization for Standalone LTE-U Networks with Randomly Delayed CSI
To coexist with Wi-Fi friendly, a standalone long-term evolution network over
unlicensed spectrum (LTE-U) under listen-before-talk (LBT) mechanism can only
access channel in a random and intermittent way, which results in random and
time-variant delay in both data and signaling transmissions. In this work, we
explore the impact of randomly delayed channel state information (CSI) on the
performance of a standalone LTE-U network by analyzing its downlink throughput
and users' energy efficiency (EE) under different CSI feedback schemes and
frequency-domain schedulers. Further, aiming at maximizing users' EE of a
standalone LTE-U network while guaranteeing fair coexistence with Wi-Fi, joint
optimization on the medium access control (MAC) protocol and CSI feedback
scheme is studied. Due to the non-convex and non-concave characteristic of the
formulated optimization problems, decomposition-based low-complexity yet
efficient algorithms are proposed. Simulation results not only verify the
analysis and the effectiveness of the proposed algorithms but also show diverse
impacts of CSI feedback scheme, frequency-domain scheduler, and traffic load of
Wi-Fi on the standalone LTE-U network performance.Comment: submitted to IEEE Transactions on Green Communications and Networkin
On Dynamic Time Division Duplex Transmissions for Small Cell Networks
Motivated by the promising benefits of dynamic Time Division Duplex (TDD), in
this paper, we use a unified framework to investigate both the technical issues
of applying dynamic TDD in homogeneous small cell networks (HomSCNs), and the
feasibility of introducing dynamic TDD into heterogeneous networks (HetNets).
First, HomSCNs are analyzed, and a small cell BS scheduler that dynamically and
independently schedules DL and UL subframes is presented, such that load
balancing between the DL and the UL traffic can be achieved. Moreover, the
effectiveness of various inter-link interference mitigation (ILIM) schemes as
well as their combinations, is systematically investigated and compared.
Besides, the interesting possibility of partial interference cancellation (IC)
is also explored. Second,based on the proposed schemes, the joint operation of
dynamic TDD together with cell range expansion (CRE) and almost blank subframe
(ABS) in HetNets is studied. In this regard, scheduling polices in small cells
and an algorithm to derive the appropriate macrocell traffic off-load and ABS
duty cycle under dynamic TDD operation are proposed. Moreover, the full IC and
the partial IC schemes are investigated for dynamic TDD in HetNets. The user
equipment (UE) packet throughput performance of the proposed/discussed schemes
is benchmarked using system-level simulations.Comment: TV