Bowen Feng

Distributed Rateless Codes with Unequal Error Protection Property for Space Information Networks

In this paper, we propose a novel distributed unequal error protection (UEP) rateless coding scheme (DURC) for space information networks (SIN). We consider the multimedia data transmissions in a dual-hop SIN communication scenario, where multiple disjoint source nodes need to transmit their UEP rateless coded data to a destination via a dynamic relay. We formulate the optimization problems to provide optimal degree distributions on the direct links and the dynamic relay links to satisfy the required error protection levels. The optimization methods are based on the And–Or tree analysis and can be solved by multi-objective programming. In addition, we evaluate the performance of the optimal DURC scheme, and simulation results show that the proposed DURC scheme can effectively provide UEP property under a variety of error requirements.

Construction of Polar Codes Concatenated to Space-Time Block Coding in MIMO System

To enhance the performance in practical communications, a novel construction of polar code is designed for a rational polar and space-time block coding (Polar-STBC) system. The Polar-STBC system can be equivalent to a single transmission channel for each polar code bit in Rayleigh fading MIMO channels, and the equivalent channel can be regarded as a fading channel, of which the gain coefficient and additive noise are studied. Moreover, the distribution of the additive noise is also derived. Finally, we show that the bit error rate performance of our Polar-STBC system in 2 × 2, 4 ×⌉ 2 and 4 ×⌉ 4 MIMOs.

Efficient Design of Polar Coded STTD Systems over Rician MIMO Channels

In this paper, a polar coded space-time transmit diversity (STTD) scheme is proposed in order to improve the performance of MIMO system. In Rician fading MIMO channels, the corresponding polar coded STTD system can be equivalent to a single transmission channel for each polar code bit. Density evolutions for the polar coded STTD systems are proposed based on the analyses of the single transmission channel. The proposed density evolutions provide preferable guidance to construct polar codes for the polar coded STTD systems. Simulation results show that the BER performance of polar coded STTD system is significantly improved as the number of antennas increases. The proposed \(2\times 2\) polar coded STTD system can provide better FER performance than LDPC-based system under low and mid code rates.

Design of Rateless Transmission Scheme Based on Punctured Polar Codes

In this paper, a parallel concatenated punctured polar (PCPP) codes is designed to realise the rateless property of polar codes. First, an improved random puncturing pattern of polar codes is proposed to archive better performance than random puncturing. Then, the optimal initial code rate is analyzed for multiple PCPP code blocks transmission in slow fading channels, which the optimal initial code rate of each new PCPP code block is determined by the overhead of the previous successful decoded code block and each packet can be transmitted with encoding construct of a 2-level PCPP codes.

An Efficient Rateless Scheme Based on the Extendibility of Systematic Polar Codes

In this paper, a new rateless scheme based on the extendibility of systematic polar codes is proposed, which is applicable for the scenario without channel state information (CSI). With detailed analyses on the existing rateless schemes, we obtain the drawbacks and difficulties which can make the schemes dysfunctional. We expound the extendibility of systematic polar codes elaborately, which forms the basis of the new rateless scheme. In addition, with the incremental redundancy hybrid automatic repeat request transmission, the new rateless scheme is established. The construction of polar codes specialized for the new scheme is also proposed, which can provide reliable performance. Comparing with the existing rateless schemes, the new scheme can be applied for arbitrary channels efficiently and reliably.

Novel polar-coded space-time transmit diversity scheme over Rician fading MIMO channels

In this paper, a polar-coded space-time transmit diversity (STTD) scheme is proposed in order to improve the performance of multiple-input multiple-output (MIMO) system. In Rician fading MIMO channels, the corresponding polar-coded STTD system can be equivalent to a single transmission channel for each polar code bit. Density evolutions for the polar-coded STTD systems are proposed based on the analyses of the single transmission channel. The proposed density evolutions provide preferable guidance to construct polar codes for the polar-coded STTD systems. Simulation results show that the BER performance of polar-coded STTD system is significantly improved as the number of antennas increases and the influence of the variable Rician K-factor of MIMO channels gradually vanishes. The proposed 2 × 2 polar-coded STTD system can provide better frame error rate (FER) performance than low-density parity-check (LDPC)-based system under low and mid code rates, and the average advantage is 0.3 dB approximately when the code rate is 0.25 and 0.2 dB when the code rate is 0.5.

Rate-Compatible Transmission Schemes Based on Parallel Concatenated Punctured Polar Codes

In this paper, an improved random puncturing pattern of polar codes is proposed, where only the frozen bits can be selected to puncture. Compared to the existing random puncturing schemes, our improved random puncturing scheme can achieve 0.2-1dB decoding performance improvement. Then, an optimized rate-compatible hybrid automatic repeat request (HARQ) transmission scheme is proposed based on parallel concatenated punctured (PCP) polar codes. By analyzing the overhead of the previous successful decoded coding block in our rate-compatible HARQ scheme, two methods of determining the optimal initial code-rate of each new PCP polar coding block are proposed over a time-varying channel. Simulation results show that the average number of retransmissions is about 1.5 times in our proposed rate-compatible HARQ schemes with a 2-level PCP polar encoding construct, which reduces half of the average number of retransmissions than the existing rate-compatible polar coding scheme.

Rateless Coding Scheme Based on Autoregressive-Moving-Average Model over Ka-Band Links

Future deep space explorations and spatial information networks (SINs) are with the increasing demands for high data rate services, the application of Ka-band channel is viewed as a primary solution. However, the Ka-band channel is much more sensitive to the weather conditions than S/C/X-band channels. In this paper, the noise temperature on Ka-band channel is modeled as N-states Markov channel, and a practical time-varying rain attenuation prediction model is proposed based on the Autoregressive-Moving-Average (ARMA) model. By considering the tradeoffs between transmission latency, reliability and power allocations consumptions, we design an adaptive rateless coding scheme based on the analog fountain codes. Simulation results show that our proposed scheme can effectively improve the throughput and efficiency.

Design of Rate-Compatible Parallel Concatenated Punctured Polar Codes for IR-HARQ Transmission Schemes

In this paper, we propose a rate-compatible (RC) parallel concatenated punctured polar (PCPP) codes for incremental redundancy hybrid automatic repeat request (IR-HARQ) transmission schemes, which can transmit multiple data blocks over a time-varying channel. The PCPP coding scheme can provide RC polar coding blocks in order to adapt to channel variations. First, we investigate an improved random puncturing (IRP) pattern for the PCPP coding scheme due to the code-rate and block length limitations of conventional polar codes. The proposed IRP algorithm only select puncturing bits from the frozen bits set and keep the information bits unchanged during puncturing, which can improve 0.2–1 dB decoding performance more than the existing random puncturing (RP) algorithm. Then, we develop a RC IR-HARQ transmission scheme based on PCPP codes. By analyzing the overhead of the previous successful decoded PCPP coding block in our IR-HARQ scheme, the optimal initial code-rate can be determined for each new PCPP coding block over time-varying channels. Simulation results show that the average number of transmissions is about 1.8 times for each PCPP coding block in our RC IR-HARQ scheme with a 2-level PCPP encoding construction, which can reduce half of the average number of transmissions than the existing RC polar coding schemes.