Layered multimedia broadcast using rateless codes with progressive recovery over cooperative MIMO

Chen Zhao, Yin Liuguo, Xu Mai, Lu, Lu Jianhua

Description

This article proposes a novel scheme, based on unequal error protected rateless codes, for broadcasting layered multimedia over cooperative multiple-input multiple-output (MIMO). By taking advantage of both cooperation and broadcasting, we first present a two-phase cooperative MIMO broadcast scheme, which exploits distributed diversity in point-to-multipoint communication scenarios. Then, to enhance layered multimedia transmission with progressive recovery, the progressive rateless codes (PRC) is proposed to recover the layered data according to their importance at the expected received ratio of all output packets. Thus, receivers with different packet loss rate can achieve an adaptive recovery of the layered multimedia progressively. Furthermore, based on PRC, a distortion-based layered multimedia broadcast problem is formulated, which optimizes source bitrate of the layered multimedia and coding rates of PRC to improve the quality of experience (QoE) of the multimedia delivery over all receivers. The performance analysis including both analytical results and simulation experiments of Motion-JPEG 2000 broadcast to receivers verifies the superiority of the cooperative broadcast and efficiency of the QoE-driven optimization algorithm.

Sujets

• Multi-user MIMO

Informations

• Publié par: biomed
• Publié le: 01 janvier 2012
• Nombre de lectures: 5
• Langue: English

Extrait

Chenetal. EURASIPJournalonWirelessCommunicationsandNetworking2012,2012:327
http://jwcn.eurasipjournals.com/content/2012/1/327
RESEARCH OpenAccess
Layeredmultimediabroadcastusingrateless
codeswithprogressiverecoveryover
cooperativeMIMO
1,3 2,3 1* 1ZhaoChen ,LiuguoYin ,MaiXu andJianhuaLu
Abstract
Thisarticleproposesanovelscheme,basedonunequalerrorprotectedratelesscodes,forbroadcastinglayered
multimediaovercooperativemultiple-inputmultiple-output(MIMO).Bytakingadvantageofbothcooperationand
broadcasting,wefirstpresentatwo-phasecooperativeMIMObroadcastscheme,whichexploitsdistributeddiversity
inpoint-to-multipointcommunicationscenarios.Then,toenhancelayeredmultimediatransmissionwithprogressive
recovery,theprogressiveratelesscodes(PRC)isproposedtorecoverthelayereddataaccordingtotheirimportance
attheexpectedreceivedratioofalloutputpackets.Thus,receiverswithdifferentpacketlossratecanachievean
adaptiverecoveryofthelayeredmultimediaprogressively.Furthermore,basedonPRC,adistortion-basedlayered
multimediabroadcastproblemisformulated,whichoptimizessourcebitrateofthelayeredmultimediaandcoding
ratesofPRCtoimprovethequalityofexperience(QoE)ofthemultimediadeliveryoverallreceivers.Theperformance
analysisincludingbothanalyticalresultsandsimulationexperimentsofMotion-JPEG2000broadcasttoreceivers
verifiesthesuperiorityofthecooperativebroadcastandefficiencyoftheQoE-drivenoptimizationalgorithm.
Keywords: Multimediabroadcast,CooperativeMIMO,Unequalerrorprotection(UEP),Ratelesscodes
Introduction receive one message in the network, where destinations
Broadcast, as the nature of the wireless medium, offers can be switched between receiving and relay modes. In
thepromiseofovercomingthebandwidthandenergylim- the receiving mode, each destination node tries to
accuitation by using one channel to transmit source data to mulate signal energy from other nodes and decodes the
all destinations simultaneously within transmission range symbolbysufficientsignal-to-noiseratio(SNR),andthen
[1].Inmanycommunicationscenarios,broadcastisoften it switches to the relay mode and retransmit the same
desired and required. Besides, multiple-input multiple- symbol. Recently, CB has been shown to provide spatial
output (MIMO) techniques can be utilized to provide diversity and achieve better bit error rate (BER)
perforhigh-rate high-quality communication services in broad- mance [3-5]. In [6], the energy efficiency of cooperative
casting. transmissionsinabroadcastnetworkisanalyzed.
Diversity, as an efficient way to mitigating the fad- In a broadcast network, multimedia contents play a key
ing arising from multipath propagation, has successfully role and mainly include the forms of text, audio, image,
been extended to relay channels by using distributed and video. For example, multimedia broadcast multicast
relay terminals, referred to as cooperative diversity [2]. service (MBMS) [7] has been proposed as a standard
In contrast with such conventional systems which have of 3GPP for providing multimedia service to users via
only one single destination node and a relatively small
broadcastin3GUMTScellularnetworks.Asthestate-ofnumber of potential relay nodes, cooperative broadcast the-artmultimediasourcecompressionstandard,scalable
(CB) [3] has been proposed for multiple destinations to videocoding(SVC)extensionoftheH.264/AVCStandard
[8] and Joint Photographic Experts Group 2000 (JPEG
2000) [9] are both pervasive in broadcast network since*Correspondence:[e-mail]
1DepartmentofElectronicEngineering,TsinghuaUniversity,Beijing,China they are capable of providing efficient video and image
Fulllistofauthorinformationisavailableattheendofthearticle
©2012Chenetal.;licenseeSpringer. ThisisanOpenAccessarticledistributedunderthetermsoftheCreativeCommons
AttributionLicense(http://creativecommons.org/licenses/by/2.0),whichpermitsunrestricteduse,distribution,andreproduction
inanymedium,providedtheoriginalworkisproperlycited.Chenetal. EURASIPJournalonWirelessCommunicationsandNetworking2012,2012:327 Page2of13
http://jwcn.eurasipjournals.com/content/2012/1/327
information content to the users. One of the most attrac- pulse signal-to-noise ratio (PSNR) evaluation is
formutions of these standards is that it is able to produce lated and optimized to improve the QoE of the broadcast
progressive recovery of videos or images by fidelity or system.TheframeworkofsuchCBschemecanbeseenin
resolution,referredtoaslayeredmultimedia. Figure 1, where a two-phase cooperative broadcasting is
In a multimedia broadcast network, layered multime- illustrated.
dia transmissions can be achieved once taking advantage
Therestofthisarticleisorganizedasfollows.In“Backof the progressive layers of JPEG 2000 or SVC. However, ground” section, we introduce some basic concepts of
considering the different importance between layers of CB and rateless codes. “Rateless codes with progressive
the layered multimedia, unequal error protection (UEP)
recovery”sectionpresentsadetaileddescriptionandperstrategies may be applied to protect the layered multime- formance analysisoftheproposedPRCfor
layeredmultidia from packet losses, in order to maximize the quality media transmission. A QoE-driven multimedia broadcast
of experience (QoE) in the network. UEP property can scheme is introduced in “QoE-driven layered multimedia
be realized by various means, one practical technique is broadcast”section.“Simulationresults”sectionshowsthe
to give different redundant information to layers by for- experimental results of the QoE-driven scheme in both
warderrorcorrection(FEC)codes.Ratelesscode[10],also CB and traditional broadcast (TB). Finally, we conclude
known as fountain codes, is one of such FEC codes with thearticlein“Conclusions”section.
capacity-achieving performance. In a rateless code, the
original source packets can accurately be recovered from
any subset of the encoding packets with the size equal to Background
or only slightly larger than the number of source packets, Cooperativebroadcast
which means that the redundant packets are maximally In general, due to the medium of wireless
communicautilized. In fact, many studies have been done in the field tion, the transmitted signals are heard not only by their
of applying rateless codes with UEP property for scalable intended receivers, but also by other neighboring nodes.
image/videostreaming[11-14]. Inconventionalpoint-to-pointcommunications,thismay
In this article, for layered multimedia broadcast over be harmful for other unintended receivers. But it will be
cooperative MIMO, progressive rateless codes (PRC) is beneficial in broadcast scenarios when one message is
proposed to apply UEP to the broadcast of Motion- needed to be transmitted to multiple destinations. In TB
aJPEG 2000 encoding layered video stream, with high schemes, the source node will provide a best-effort
transefficiency and low complexity. Beyond the proposed mission service under energy constraint. Each message
PRC, unequal error protected broadcast scheme is estab- is broadcasted only once. Some destination nodes with
lished with the purpose that different users can receive
lowerreceivingSNRwillbeunabletoreceivethemesbroadcasting images/videos with different decoding lay- sage, which leads to a higher packet loss probability. If
ers according to their channel qualities. Meanwhile, a thereceivingSNRisbelowacriticalvalue,thedestination
distortion-based model of the broadcast scheme using node cannot even collect one whole packet. Such node
Destination N
M +11
M1+1
Destination N1
1
Destination NM +21
M1+2
Destination N2
2
Phase 1 Phase 2
Layered NS
Source
Destination NM−1
M-1
Destination NM
1
M1
Destination NM
M
Figure1FrameworkoftheproposedCBscheme.Mdestinationnodeswithmultipleantennasaredistributedaroundthesourcenode,among
whichM nodesswitchtorelaymodeinRBphase.1Chenetal. EURASIPJournalonWirelessCommunicationsandNetworking2012,2012:327 Page3of13
http://jwcn.eurasipjournals.com/content/2012/1/327
is called to be out of the coverage of the source node. thisarticle.Withthediversitygainofvirtualarray,thePLR
To broaden the coverage of the source node and improve ofdestinationnodesareallincreased,especiallyforthose
the SNR of bad receivers, it is better to utilize multi- whose PLRs are critically low. Thus, the coverage of the
hop to relay the message to distributed receivers, where source node is considerably expanded. Note that though
cooperativediversitycanbeexploited[3,4]. CB can improve the reliability of broadcasting efficiently,
We consider a CB scheme over quasi-static flat-fading the system throughput is halved due to the relay phase.
channels as shown in Figure 1. There are one source
So,aselectionstrategyisrequiredtoobtainbetterperfornodeandMdestinationreceivingnodesdistributedinthe mance between cooperation and non-cooperation, which
scheme. All nodes are equipped with multiple antennas. willbediscussedin“Simulationresults”section.
We denote N asthenumberofantennasofthesourceS
node, N as the number of antennas of destination node Ratelesscodesm
m,where1 ≤ m ≤ M. Following [4],assume a two-phase Luby transform (LT) codes [15] or Raptor codes [16],
decode-and-forward (DF) CB protocol. The two phases as two state-of-