Aerospace and Electronic Systems Magazine April 2017 - 49

path. This is considered a disadvantage. For its application in a
DTN-based space network, this information will typically be unavailable. Therefore, it is reasonable to consider at present applying erasure coding at the convergence layer of DTN, as needed, on
a hop-by-hop basis. Specifically, erasure coding is most urgently
needed on long-latency space links served by the LTP convergence
layer adapter, i.e., in the erasure coding of LTP segments.
As a type of the classical erasure codes, the Reed-Solomon (RS)
codes [19] are broadly used in digital communications and data storage. The RS codes had superior performance and maturity in satellite
and space communications. The Consultative Committee for Space
Data Systems (CCSDS) has adopted the RS codes as the space channel
coding standard [15]. It is reasonable to integrate RS coding with LTP
for its use in space-based DTN. That is the motivation of this work.
In this article, we propose a new "local data-link layer" protocol to space DTN protocol stack, simply named RS-LTP, that integrates RS erasure coding to LTP for more efficient data delivery
in space communication networks. The transmission performance
of RS-LTP is studied based on data delivery experiments using an
emulated space communication testbed infrastructure to evaluate
the performance advantage of RS-LTP over LTP (without RS coding implemented). We intend to evaluate quantitatively how the RS
erasure codes can improve the performance of DTN's LTP operating data delivery over a DTN-based lossy space channel.

AN OVERVIEW OF REED-SOLOMON CODES, LTP AND
DESIGN OF RS-LTP
REED-SOLOMON CODES
As the block-based error-control codes, RS codes are widely recognized as a core code type used in modern digital communication systems. In particular, they have been frequently used for error
correction over satellite and space channels. This motivated us for
choosing them for this work. RS codes have been adopted as the CCAPRIL 2017

SDS space channel coding standard and have been implemented in
the CCSDS Space Communications Protocol Specifications (SCPS)
as a form of FEC [15]. One of their well-known applications was
encoding the digital pictures sent back by the Voyager deep-space
mission. In the Voyager mission, RS coding was introduced to be
concatenated with convolutional codes, a practice that has since become very widespread in satellite and space communications.
From the perspective of the error-correcting capability, RS
codes belong to the class of non-binary cyclic error-correcting
codes. They constitute an efficient class of linear codes using multibit symbols and have the capability of correcting/detecting multiple symbol errors and correcting symbol erasures. Two types of
RS codes, Cauchy-RS and Vandermonde-RS, are generally used to
overcome the unreliable nature of data transmission over channels
subject to erasures. The number and type of errors that the RS codes
can correct are different depending on the characteristics of the RS
codes adopted. For an RS code RS(n, k), where n is the code length
and k is the information length, it can correct up to t = (n−k)/2 random symbol errors and up to (n-k) symbol erasures [19].
From the perspectives of RS codes operation and performance,
assuming k source packets are to be encoded, the source generates n coding packets where n exceeds k as dictated by the RS
coding rule. These n coding packets are transmitted to the destination through the network. As long as the number of coding packets
received by the receiver, m, is greater than or equal to the number
of source packets k (i.e., m>k or m=k), all source packets can be
recovered. It has been found that transmission performance with
RS coding is very close to the Shannon limit, especially when short
codes and medium codes are used. For the details of the construction, properties, and error correction algorithms of the RS codes,
refer to [19] and other related literatures.

OVERVIEW OF LICKLIDER TRANSMISSION PROTOCOL (LTP)
The LTP CLA is among the most broadly supported adapters under BP, and it provides an interface for BP to operate with the un-

IEEE A&E SYSTEMS MAGAZINE

49



Table of Contents for the Digital Edition of Aerospace and Electronic Systems Magazine April 2017

No label
Aerospace and Electronic Systems Magazine April 2017 - No label
Aerospace and Electronic Systems Magazine April 2017 - Cover2
Aerospace and Electronic Systems Magazine April 2017 - 1
Aerospace and Electronic Systems Magazine April 2017 - 2
Aerospace and Electronic Systems Magazine April 2017 - 3
Aerospace and Electronic Systems Magazine April 2017 - 4
Aerospace and Electronic Systems Magazine April 2017 - 5
Aerospace and Electronic Systems Magazine April 2017 - 6
Aerospace and Electronic Systems Magazine April 2017 - 7
Aerospace and Electronic Systems Magazine April 2017 - 8
Aerospace and Electronic Systems Magazine April 2017 - 9
Aerospace and Electronic Systems Magazine April 2017 - 10
Aerospace and Electronic Systems Magazine April 2017 - 11
Aerospace and Electronic Systems Magazine April 2017 - 12
Aerospace and Electronic Systems Magazine April 2017 - 13
Aerospace and Electronic Systems Magazine April 2017 - 14
Aerospace and Electronic Systems Magazine April 2017 - 15
Aerospace and Electronic Systems Magazine April 2017 - 16
Aerospace and Electronic Systems Magazine April 2017 - 17
Aerospace and Electronic Systems Magazine April 2017 - 18
Aerospace and Electronic Systems Magazine April 2017 - 19
Aerospace and Electronic Systems Magazine April 2017 - 20
Aerospace and Electronic Systems Magazine April 2017 - 21
Aerospace and Electronic Systems Magazine April 2017 - 22
Aerospace and Electronic Systems Magazine April 2017 - 23
Aerospace and Electronic Systems Magazine April 2017 - 24
Aerospace and Electronic Systems Magazine April 2017 - 25
Aerospace and Electronic Systems Magazine April 2017 - 26
Aerospace and Electronic Systems Magazine April 2017 - 27
Aerospace and Electronic Systems Magazine April 2017 - 28
Aerospace and Electronic Systems Magazine April 2017 - 29
Aerospace and Electronic Systems Magazine April 2017 - 30
Aerospace and Electronic Systems Magazine April 2017 - 31
Aerospace and Electronic Systems Magazine April 2017 - 32
Aerospace and Electronic Systems Magazine April 2017 - 33
Aerospace and Electronic Systems Magazine April 2017 - 34
Aerospace and Electronic Systems Magazine April 2017 - 35
Aerospace and Electronic Systems Magazine April 2017 - 36
Aerospace and Electronic Systems Magazine April 2017 - 37
Aerospace and Electronic Systems Magazine April 2017 - 38
Aerospace and Electronic Systems Magazine April 2017 - 39
Aerospace and Electronic Systems Magazine April 2017 - 40
Aerospace and Electronic Systems Magazine April 2017 - 41
Aerospace and Electronic Systems Magazine April 2017 - 42
Aerospace and Electronic Systems Magazine April 2017 - 43
Aerospace and Electronic Systems Magazine April 2017 - 44
Aerospace and Electronic Systems Magazine April 2017 - 45
Aerospace and Electronic Systems Magazine April 2017 - 46
Aerospace and Electronic Systems Magazine April 2017 - 47
Aerospace and Electronic Systems Magazine April 2017 - 48
Aerospace and Electronic Systems Magazine April 2017 - 49
Aerospace and Electronic Systems Magazine April 2017 - 50
Aerospace and Electronic Systems Magazine April 2017 - 51
Aerospace and Electronic Systems Magazine April 2017 - 52
Aerospace and Electronic Systems Magazine April 2017 - 53
Aerospace and Electronic Systems Magazine April 2017 - 54
Aerospace and Electronic Systems Magazine April 2017 - 55
Aerospace and Electronic Systems Magazine April 2017 - 56
Aerospace and Electronic Systems Magazine April 2017 - 57
Aerospace and Electronic Systems Magazine April 2017 - 58
Aerospace and Electronic Systems Magazine April 2017 - 59
Aerospace and Electronic Systems Magazine April 2017 - 60
Aerospace and Electronic Systems Magazine April 2017 - 61
Aerospace and Electronic Systems Magazine April 2017 - 62
Aerospace and Electronic Systems Magazine April 2017 - 63
Aerospace and Electronic Systems Magazine April 2017 - 64
Aerospace and Electronic Systems Magazine April 2017 - 65
Aerospace and Electronic Systems Magazine April 2017 - 66
Aerospace and Electronic Systems Magazine April 2017 - 67
Aerospace and Electronic Systems Magazine April 2017 - 68
Aerospace and Electronic Systems Magazine April 2017 - 69
Aerospace and Electronic Systems Magazine April 2017 - 70
Aerospace and Electronic Systems Magazine April 2017 - 71
Aerospace and Electronic Systems Magazine April 2017 - 72
Aerospace and Electronic Systems Magazine April 2017 - 73
Aerospace and Electronic Systems Magazine April 2017 - 74
Aerospace and Electronic Systems Magazine April 2017 - 75
Aerospace and Electronic Systems Magazine April 2017 - 76
Aerospace and Electronic Systems Magazine April 2017 - 77
Aerospace and Electronic Systems Magazine April 2017 - 78
Aerospace and Electronic Systems Magazine April 2017 - 79
Aerospace and Electronic Systems Magazine April 2017 - 80
Aerospace and Electronic Systems Magazine April 2017 - 81
Aerospace and Electronic Systems Magazine April 2017 - 82
Aerospace and Electronic Systems Magazine April 2017 - 83
Aerospace and Electronic Systems Magazine April 2017 - 84
Aerospace and Electronic Systems Magazine April 2017 - 85
Aerospace and Electronic Systems Magazine April 2017 - 86
Aerospace and Electronic Systems Magazine April 2017 - 87
Aerospace and Electronic Systems Magazine April 2017 - 88
Aerospace and Electronic Systems Magazine April 2017 - 89
Aerospace and Electronic Systems Magazine April 2017 - 90
Aerospace and Electronic Systems Magazine April 2017 - 91
Aerospace and Electronic Systems Magazine April 2017 - 92
Aerospace and Electronic Systems Magazine April 2017 - 93
Aerospace and Electronic Systems Magazine April 2017 - 94
Aerospace and Electronic Systems Magazine April 2017 - 95
Aerospace and Electronic Systems Magazine April 2017 - 96
Aerospace and Electronic Systems Magazine April 2017 - 97
Aerospace and Electronic Systems Magazine April 2017 - 98
Aerospace and Electronic Systems Magazine April 2017 - 99
Aerospace and Electronic Systems Magazine April 2017 - 100
Aerospace and Electronic Systems Magazine April 2017 - 101
Aerospace and Electronic Systems Magazine April 2017 - 102
Aerospace and Electronic Systems Magazine April 2017 - 103
Aerospace and Electronic Systems Magazine April 2017 - 104
Aerospace and Electronic Systems Magazine April 2017 - Cover3
Aerospace and Electronic Systems Magazine April 2017 - Cover4
http://www.brightcopy.net/allen/aesm/34-2s
http://www.brightcopy.net/allen/aesm/34-2
http://www.brightcopy.net/allen/aesm/34-1
http://www.brightcopy.net/allen/aesm/33-12
http://www.brightcopy.net/allen/aesm/33-11
http://www.brightcopy.net/allen/aesm/33-10
http://www.brightcopy.net/allen/aesm/33-09
http://www.brightcopy.net/allen/aesm/33-8
http://www.brightcopy.net/allen/aesm/33-7
http://www.brightcopy.net/allen/aesm/33-5
http://www.brightcopy.net/allen/aesm/33-4
http://www.brightcopy.net/allen/aesm/33-3
http://www.brightcopy.net/allen/aesm/33-2
http://www.brightcopy.net/allen/aesm/33-1
http://www.brightcopy.net/allen/aesm/32-10
http://www.brightcopy.net/allen/aesm/32-12
http://www.brightcopy.net/allen/aesm/32-9
http://www.brightcopy.net/allen/aesm/32-11
http://www.brightcopy.net/allen/aesm/32-8
http://www.brightcopy.net/allen/aesm/32-7s
http://www.brightcopy.net/allen/aesm/32-7
http://www.brightcopy.net/allen/aesm/32-6
http://www.brightcopy.net/allen/aesm/32-5
http://www.brightcopy.net/allen/aesm/32-4
http://www.brightcopy.net/allen/aesm/32-3
http://www.brightcopy.net/allen/aesm/32-2
http://www.brightcopy.net/allen/aesm/32-1
http://www.brightcopy.net/allen/aesm/31-12
http://www.brightcopy.net/allen/aesm/31-11s
http://www.brightcopy.net/allen/aesm/31-11
http://www.brightcopy.net/allen/aesm/31-10
http://www.brightcopy.net/allen/aesm/31-9
http://www.brightcopy.net/allen/aesm/31-8
http://www.brightcopy.net/allen/aesm/31-7
https://www.nxtbookmedia.com