2 research outputs found
Information-Theoretic Study on Routing Path Selection in Two-Way Relay Networks
Two-way relaying is a promising technique to improve network throughput.
However, how to apply it to a wireless network remains an unresolved issue.
Particularly, challenges lie in the joint design between the physical layer and
the routing protocol. Applying an existing routing protocol to a two-way relay
network can easily compromise the advantages of two-way relaying. Considering
routing path selection and two-way relaying together can be formulated as a
network optimization problem, but it is usually NP-hard. In this paper, we take
a different approach to study routing path selection for two-way relay
networks. Instead of solving the joint optimization problem, we study the
fundamental characteristics of a routing path consisting of multihop two-way
relaying nodes. Information theoretical analysis is carried out to derive
bandwidth efficiency and energy efficiency of a routing path in a two-way relay
network. Such analysis provides a framework of routing path selection by
considering bandwidth efficiency, energy efficiency and latency subject to
physical layer constraints such as the transmission rate, transmission power,
path loss exponent, path length, and the number of relays. This framework
provides insightful guidelines on routing protocol design of a two-way relay
network. Our analytical framework and insights are illustrated by extensive
numerical results
A Survey on MIMO Transmission with Discrete Input Signals: Technical Challenges, Advances, and Future Trends
Multiple antennas have been exploited for spatial multiplexing and diversity
transmission in a wide range of communication applications. However, most of
the advances in the design of high speed wireless multiple-input multiple
output (MIMO) systems are based on information-theoretic principles that
demonstrate how to efficiently transmit signals conforming to Gaussian
distribution. Although the Gaussian signal is capacity-achieving, signals
conforming to discrete constellations are transmitted in practical
communication systems. As a result, this paper is motivated to provide a
comprehensive overview on MIMO transmission design with discrete input signals.
We first summarize the existing fundamental results for MIMO systems with
discrete input signals. Then, focusing on the basic point-to-point MIMO
systems, we examine transmission schemes based on three most important criteria
for communication systems: the mutual information driven designs, the mean
square error driven designs, and the diversity driven designs. Particularly, a
unified framework which designs low complexity transmission schemes applicable
to massive MIMO systems in upcoming 5G wireless networks is provided in the
first time. Moreover, adaptive transmission designs which switch among these
criteria based on the channel conditions to formulate the best transmission
strategy are discussed. Then, we provide a survey of the transmission designs
with discrete input signals for multiuser MIMO scenarios, including MIMO uplink
transmission, MIMO downlink transmission, MIMO interference channel, and MIMO
wiretap channel. Additionally, we discuss the transmission designs with
discrete input signals for other systems using MIMO technology. Finally,
technical challenges which remain unresolved at the time of writing are
summarized and the future trends of transmission designs with discrete input
signals are addressed.Comment: 110 pages, 512 references, submit to Proceedings of the IEE