2,095 research outputs found
Polar-Coded Pulse Position Modulation for the Poisson Channel
A polar-coded modulation scheme for deep-space optical communication is
proposed. The photon counting Poisson channel with pulse position modulation
(PPM) is considered. We use the fact that PPM is particularly well suited to be
used with multilevel codes to design a polar-coded modulation scheme for the
system in consideration. The construction of polar codes for the Poisson
channel based on Gaussian approximation is demonstrated to be accurate. The
proposed scheme uses a cyclic redundancy check outer code and a successive
cancellation decoder with list decoding and it is shown that it outperforms the
competing schemes.Comment: 7 pages, 9 figure
Space-Time Signal Design for Multilevel Polar Coding in Slow Fading Broadcast Channels
Slow fading broadcast channels can model a wide range of applications in
wireless networks. Due to delay requirements and the unavailability of the
channel state information at the transmitter (CSIT), these channels for many
applications are non-ergodic. The appropriate measure for designing signals in
non-ergodic channels is the outage probability. In this paper, we provide a
method to optimize STBCs based on the outage probability at moderate SNRs.
Multilevel polar coded-modulation is a new class of coded-modulation techniques
that benefits from low complexity decoders and simple rate matching. In this
paper, we derive the outage optimality condition for multistage decoding and
propose a rule for determining component code rates. We also derive an upper
bound on the outage probability of STBCs for designing the
set-partitioning-based labelling. Finally, due to the optimality of the
outage-minimized STBCs for long codes, we introduce a novel method for the
joint optimization of short-to-moderate length polar codes and STBCs
Throughput-based Design for Polar Coded-Modulation
Typically, forward error correction (FEC) codes are designed based on the
minimization of the error rate for a given code rate. However, for applications
that incorporate hybrid automatic repeat request (HARQ) protocol and adaptive
modulation and coding, the throughput is a more important performance metric
than the error rate. Polar codes, a new class of FEC codes with simple rate
matching, can be optimized efficiently for maximization of the throughput. In
this paper, we aim to design HARQ schemes using multilevel polar
coded-modulation (MLPCM). Thus, we first develop a method to determine a
set-partitioning based bit-to-symbol mapping for high order QAM constellations.
We simplify the LLR estimation of set-partitioned QAM constellations for a
multistage decoder, and we introduce a set of algorithms to design
throughput-maximizing MLPCM for the successive cancellation decoding (SCD).
These codes are specifically useful for non-combining (NC) and Chase-combining
(CC) HARQ protocols. Furthermore, since optimized codes for SCD are not optimal
for SC list decoders (SCLD), we propose a rate matching algorithm to find the
best rate for SCLD while using the polar codes optimized for SCD. The resulting
codes provide throughput close to the capacity with low decoding complexity
when used with NC or CC HARQ
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