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

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

Irregular multidimensional constellations for orthogonal STBCs

Utilizing multiple antennas at the transmitter and receiver provides higher data rates and better reliability by exploiting spatial diversity. Space-time block codes (STBCs) is a simple approach for using multiple transmit and receive antennas that has been widely employed in standards. The STBCs introduced in the literature use independent two-dimensional constellations, while the performance of orthogonal STBCs may be improved with multidimensional constellations. These constellations are transmitted by combining multiple space-time resources to form a multidimensional signal space. In this paper, we propose a method for finding optimized multidimensional constellations for orthogonal STBCs. Optimization is performed by minimizing a novel bound on the block or symbol error rate. We show that a substantial improvement in the error probability can be achieved with these novel constellations

Polar coded multi-antenna multidimensional constellations in partially coherent channels

As one of the multiple-input-multiple-output (MIMO) techniques that work close to capacity, Hochwald and ten Brink proposed to send forward error correction (FEC) coded two-dimensional symbols from multiple antennas in each time slot and decode them using a maximum likelihood decoder. This can be generally considered as the transmission of multidimensional symbols in each time slot and here is referred to as multi-antenna multidimensional constellations (MMCs). Polar codes are a new class of forward error correction codes that benefit from simple rate matching and low complexity decoders, and therefore, facilitate the design of efficient systems. Due to the availability of partial channel state information at the receiver in time varying fading systems, the performance of uncoded MMCs can be improved by employing MMCs designed for partially coherent systems. However, the choice of the constellation in presence of FEC codes is of importance. In this paper, we propose the concatenation of the polar codes and MMC as a high-performance scheme for time varying fading systems. We further study different methods of design of the scheme in partially coherent systems and discuss the choice of the constellation

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 codedmodulation (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 throughputmaximizing 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

Effects of various water storage methods on plantation of Greek juniper (Juniperus excelsa M. B.)

This research was carried out in Sirachal Research Station in order to identify the best method for Greek juniper (Juniperus excelsa M. B.) afforestation as one of the most important forest species in Iran. Three year-old juniper saplings were transported to Sirachal and were planted in a Split-Plot Randomized Block Design with water harvesting (in 5 treatments including using organs of native plants and shrubs at the bottom of pits, using 1×1 m plastic film at the surface of pits, using Aquasorb polymers mixed with the pits soil, semi-circular bonds and control) as main factor and shading (in 2 level of using tree sprouts as artificial shading and control) as secondary factor in 3 replication and 16 saplings per replication. Measured variables were survival, collar diameter, height, and crown area and sapling vitality at the end of growing season of 2015 and 2016. Results showed that rainwater harvesting had significant effect on survival juniper saplings for both 2014 and 2015 years and current annual increment of collar diameter. The highest value of these parameters was noticed for plastic film treatment though the highest decrease of survival from 2014 to 2015 was noticed for this treatment too. Both rainwater harvesting and shading had no significant effect on height, crown area, vitality and their changes during the studied years. Overall, results confirmed the possibility of rainfed afforestation of Greek juniper in high altitude of Southern Alborz Mountain. To achieve this goal, usage of nylon at the surface of plantation pits is recommended. There is no need to use artificial shading for planted saplings