The Consultative Committee for Spac

The Consultative Committee for Space Data Systems
CCSDS) has produced over the years a de facto standard

(
for all space-related communication systems. In the latest
versions of the standard [1] there has been an increment in
the foreseen downlink throughput for deep-space
communications, reaching up to tens of megabits per
second. Four channel coding schemes have been described
in [2] and consequently assembled into application-wise
forward-error-correction (FEC) schemes in [3]. Both turbo
[
4] and low-density-parity-check (LDPC) [5] codes are
currently contemplated for deep-space communications
[2]; while the suggested turbo codes target stricter bit error
rate (BER) constraints, LDPC codes have been recently
included in the standard and have higher rate, and they are
currently subject to CCSDS experimentation [6]. Both
turbo and LDPC codes are common in on-Earth wireless
communication systems; however, throughput
requirements are much higher than those for deep-space
communications, while frame error rate (FER) constraints
are more relaxed. In fact, spacecraft-to-Earth
communications are characterized by limited amounts of
available power and long transmission times, and a failed
reception and consequent retransmission are often
unacceptable. Thus, ad hoc powerful FEC schemes must
be devised.
A FEC relying on the serial concatenation of turbo and
LDPC codes has been proposed in [7]; thanks to its very
good error correction capabilities, it has been deemed
suitable for the extremely critical deep-space

communications. To the best of our knowledge, no
implementation solution for the concatenated scheme has
been proposed so far, but decoders for both turbo and
LDPC codes are present in the state of the art, mainly
targeting wireless communications. Multicode and
multistandard decoders that make flexibility their primary
concern have also been introduced recently [8–13]; they
are characterized by different degrees of datapath and
memory sharing.
This work proposes a decoder for concatenated turbo
and LDPC codes targeting deep-space communications.
The usage of the same decoding algorithm for both codes
greatly reduces the area overhead of the concatenated
scheme decoder with respect to a single LDPC or turbo
code decoder. In fact, it allows one to exploit a high degree
of datapath sharing and obtain very low power consumption
and area occupation. In addition to deep-space
communications, the proposed solution could be also
useful in further applications where retransmission of lost
packets is not allowed, such as, for example, broadcasting.
The rest of the paper is organized as follows: Section II
introduces turbo and LDPC code decoding, while
Section III describes the concatenated FEC schemes and
their performance. The hardware structure of the proposed
decoder is explained in Section IV, and Section V gives
the results of the implementation. Finally, conclusions are

drawn in Section VI.

結果 (中文) 1:

空间数据系统咨询委员会CCSDS) 产生了多年来事实上的标准(对于所有与空间有关的通信系统。在最新版本的标准 [1] 那里一直在增量对于深太空预见下行链路的吞吐量通信，达到达几十兆比特每第二次。介绍了四种信道编码方案在 [2]，因此组装成 application-wise[3] 中的前向纠错 (FEC) 计划。这两个涡轮增压[4] 和低密度奇偶校验码 (LDPC) [5] 代码是目前正在考虑为深空通信[2];同时建议的 turbo 码目标严格误比特率率 (BER) 约束，LDPC 码最近一直在在该标准内具有较高的速度，和他们目前受 CCSDS 实验 [6]。两个涡轮增压和 LDPC 码是共同在地球上无线通信系统;然而，吞吐量要求是高于深空间通信，同时帧错误 (FER) 率约束是更轻松。事实上，太空船地球通信的特点是数量有限的可用的电源和长的传输时间，和失败接待和随之而来的重传往往无法接受。因此，特设强大 FEC 方案必须订定。FEC 依靠涡轮串行级联和在 [7]; 提出了 LDPC 码由于对其非常好的错误校正功能，它被认为是suitable for the extremely critical deep-spacecommunications. To the best of our knowledge, noimplementation solution for the concatenated scheme hasbeen proposed so far, but decoders for both turbo andLDPC codes are present in the state of the art, mainlytargeting wireless communications. Multicode andmultistandard decoders that make flexibility their primaryconcern have also been introduced recently [8–13]; theyare characterized by different degrees of datapath andmemory sharing.This work proposes a decoder for concatenated turboand LDPC codes targeting deep-space communications.The usage of the same decoding algorithm for both codesgreatly reduces the area overhead of the concatenatedscheme decoder with respect to a single LDPC or turbocode decoder. In fact, it allows one to exploit a high degreeof datapath sharing and obtain very low power consumptionand area occupation. In addition to deep-spacecommunications, the proposed solution could be alsouseful in further applications where retransmission of lostpackets is not allowed, such as, for example, broadcasting.The rest of the paper is organized as follows: Section IIintroduces turbo and LDPC code decoding, whileSection III describes the concatenated FEC schemes and their performance. The hardware structure of the proposeddecoder is explained in Section IV, and Section V givesthe results of the implementation. Finally, conclusions are第六节绘制。

結果 (中文) 3:

空间数据系统咨询委员会CCSDS）多年来一直在制作阿德的事实上的标准（所有的空间相关的通信系统。在最新的标准的[ 1 ]有一个增量版本可以预见的下行链路吞吐量的深空通信，达到几十兆比特每二。四信道编码方案进行了描述在[ 2 ]，因此组装成应用智慧前向纠错（FEC）在[ 3计划]。涡轮【4 ]和低密度奇偶校验（LDPC）[ 5 ]码目前设想用于深空通信[ 2 ]；而提出的Turbo码的目标更严格的误码率（BER）的限制，LDPC码已被最近纳入标准，具有更高的速度，和他们目前受CCSDS实验[ 6 ]。两Turbo码和LDPC码是常见的在地球无线通信系统；然而，吞吐量要求比深空高多了通信，而帧错误率（FER）约束更轻松。事实上，宇宙飞船到地球通信的特点是数量有限的可用功率和较长的传输时间，一个失败的接待和随之而来的转播往往不可接受的。因此，Ad Hoc网络强大的FEC方案必须设计。一个FEC依托Turbo码的串行级联和LDPC码已在[ 7 ]提出的；由于其非常好的纠错能力，它已被视为适用于极为关键的深空通信。尽我们所知，没有实施方案为级联方案被提出至今，但两个涡轮增压器和解码器LDPC码是在艺术的状态存在，主要瞄准无线通信。Multicode和多标准解码器的灵活性使fl原关注还介绍了最近8–[ 13 ]；他们具有不同程度的数据通路和内存共享。本文提出了一种级联的Turbo解码器针对深空通信和LDPC码。相同的译码算法代码的使用大大降低了级联的面积开销相对于一个LDPC或Turbo解码器编码解码器。事实上，它可以利用高度对数据共享和获取极低的功耗面积占用。除了深空通信，提出的解决方案也可以在进一步的应用中，重传丢失的有用包是不允许的，例如，例如，广播。本文的其余部分安排如下：第二节介绍了Turbo码和LDPC码的译码，而第三节介绍了级联FEC方案他们的表现。提出的硬件结构解码器是在第四节和第五节给出解释，实施的结果。最后，结论是画在第六