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:

The Consultative Committee for Space Data SystemsCCSDS) has produced over the years a de facto standard(for all space-related communication systems. In the latestversions of the standard [1] there has been an increment inthe foreseen downlink throughput for deep-spacecommunications, reaching up to tens of megabits persecond. Four channel coding schemes have been describedin [2] and consequently assembled into application-wiseforward-error-correction (FEC) schemes in [3]. Both turbo[4] and low-density-parity-check (LDPC) [5] codes arecurrently contemplated for deep-space communications[2]; while the suggested turbo codes target stricter bit errorrate (BER) constraints, LDPC codes have been recentlyincluded in the standard and have higher rate, and they arecurrently subject to CCSDS experimentation [6]. Bothturbo and LDPC codes are common in on-Earth wirelesscommunication systems; however, throughputrequirements are much higher than those for deep-spacecommunications, while frame error rate (FER) constraintsare more relaxed. In fact, spacecraft-to-Earthcommunications are characterized by limited amounts ofavailable power and long transmission times, and a failedreception and consequent retransmission are oftenunacceptable. Thus, ad hoc powerful FEC schemes mustbe devised.A FEC relying on the serial concatenation of turbo andLDPC codes has been proposed in [7]; thanks to its verygood error correction capabilities, it has been deemed适用于极为关键的深层空间通信。到我们所知，没有串联的计划的实施方案已已建议到目前为止，但解码器，这两个涡轮增压和LDPC 码是目前最先进的在主要针对无线通信。码和让宜家他们小学的多标准解码器关注也介绍了最近 [8-13];他们特点是不同程度的数据通路和共享内存。这项工作提出了一个解码器，串联的涡轮增压和 LDPC 码靶向深空通信。这两个代码相同的解码算法的使用大大降低了串联的地区开销对于单一的 ldpc 码或涡轮增压方案解码器编码解码器。事实上，它允许用户利用程度高数据通路分享和获得极低的功耗和地区占领。除了深空间通信，提出的解决方案也可能在进一步应用程序的重传丢的地方有用数据包不是允许，如，例如，广播。剩下的纸有组织如下︰ 第二节介绍了涡轮增压和 LDPC 码解码，而第三节描述串联的 FEC 方案和他们的表现。硬件结构的建议解码器解释在第四节和第五节给出了执行的结果。最后，结论是第六节绘制。

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