Error Control Coding
Error-control coding techniques are of
paramount importance to increase the reliability of wireless communications
links. In 5G and beyond systems, the requirements of reduced energy
consumption, quality of service, high data rates and low latency pose
challenges for the design of space-time, network and channel codes and the
development of decoding algorithms.
In our research, the design of channel codes
focuses on short block lengths in order to reduce the latency. Turbo and
low-density parity-check (LDPC) and polar codes are investigated for 5G and
beyond wireless systems and applications to cellular, Internet of things (IoT) and sensor networks. The design of turbo techniques
can be improved by careful adjustment of the interleaving structures as well as
the exploitation of prior knowledge about channel fading. LDPC and polar code
design can be improved by optimizing the graph connections and enhancing its
connectivity. Current work on decoding techniques for polar and LDPC codes
focuses on the improvement of performance through scheduling and reweighting
techniques along with the development algorithmic solutions with a focus on
high performance, low-complexity implementation, low latency. Key problems in
the design of channel codes and the development of decoding algorithms for 5G
and beyond networks include the limitation of existing designs for short blocks
which are performance limited, hardware impairments, limitations imposed by
cycles and deficiencies in the exchange of log-likelihood ratios. In our 5G and
beyond lab, we look at innovative solutions to the problems encountered in the
design of precoders, namely:
o
LDPC
and polar code design for short block lengths
o
High-performance decoding algorithms
o
Low-complexity
and reduced-latency implementations
Work on space-time coding and physical-layer
network coding techniques has recently focused on the design of space-time
codes for sensor networks and device-to-device communications. Specifically, we
are currently investigating distributed space-time coding approaches with
feedback channels based on optimization techniques. We are also looking at power allocation
strategies, delay-tolerant techniques and physical-layer network coding
concepts. Key topics in the design of space-time coding and physical-layer
networking coding for 5G and beyond networks include the limitation of existing
algorithms to imperfect channel state information, relays equipped with
buffers, resource allocation across different devices and applications to
cellular networks. In our 5G and beyond lab, we look at innovative solutions
and the following topics:
o
Low-complexity
distributed space-time coding algorithms
o
Buffer-aided
relay concepts
o
Resource
allocation techniques
o
Combined
distributed space-time coding and network coding strategies
Selected Publications:
R. M. Oliveira and R. C. de Lamare,
"Rate-Compatible Polar Codes Based on Polarization-Driven
Shortening," in IEEE Communications Letters, vol. 22, no. 10, pp.
1984-1987, Oct. 2018. pdf
C. Healy, Z. Shao, R. M. Oliveira, R. C. de Lamare and
L. L. Mendes, "Knowledge-aided informed dynamic scheduling for LDPC
decoding of short blocks," in IET Communications, vol. 12, no. 9, pp.
1094-1101, vol. 5, no. 6, 2018. pdf
A. G. D. Uchoa, C. T. Healy
and R. C. de Lamare, ``Iterative Detection and Decoding Algorithms For MIMO Systems in Block-Fading Channels using LDPC Codes”,
IEEE Transactions on Vehicular Technology, 2015. pdf
codes
A. G. D. Uchoa, C. T. Healy
and R. C. de Lamare , ``Structured Root-Check LDPC
Codes and PEG-Based Techniques for Block-Fading Channels”, EURASIP Journal on
Wireless Communications and Networking, 2015. pdf
J. Liu and R.
C. de Lamare, “Low-Latency Reweighted Belief Propagation Decoding for LDPC
Codes”, IEEE Communications Letters, 2012. pdf
C. T. Healy and R. C. de Lamare, “Decoder-Optimised Progressive Edge Growth Algorithms for the Design
of LDPC Codes with Low Error Floors”, IEEE Communications Letters,
2012. pdf
A. G. D. Uchoa, C. T. Healy,
R. C. de Lamare and R. D. Souza, “Design of LDPC Codes Based on Progressive
Edge Growth Techniques For Block Fading Channels”, IEEE Communications Letters,
2011. pdf
T. Peng, R. C. de Lamare and A. Schmeink, ``Adaptive Distributed Space-Time Coding Based on
Adjustable Code Matrices for Cooperative MIMO Relaying Systems”, IEEE
Transactions on Communications, 2013. pdf
P. Li and R. C. de Lamare, "Distributed Iterative
Detection with Reduced Message Passing for Networked MIMO Cellular
Systems", IEEE Transactions on Vehicular Technology, 2014. pdf
R. C. de Lamare, "Adaptive and Iterative
Multi-Branch MMSE Decision Feedback Detection Algorithms for Multi-Antenna
Systems", IEEE Transactions on Wireless Communications, October 2013. pdf
P. Li, R. C. de Lamare and R. Fa, “Multiple Feedback
Successive Interference Cancellation Detection for Multiuser MIMO Systems”,
IEEE Transactions on Wireless Communications, 2011. pdf
Matlab Codes and Tools:
Precoding algorithms – codes
Detection algorithms - codes
LDPC-coded detection algorithms - codes