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en:group:seminars:20051031 [2009/04/07 11:17] external edit
en:group:seminars:20051031 [2016/06/23 11:26] (current)
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 ==== abstract ==== ==== abstract ====
 There has recently been and continues to be a large amount of work in  There has recently been and continues to be a large amount of work in 
 +cellular commercial standards that is focused on multimedia delivery using
 +broadcast and multicast channels. ​ The reasons for these standardization
 +efforts are self-evident:​ while cellular services become ever more popular
 +and as cellular multimedia applications grow richer, the available bandwidth
 +for delivering these services remains fairly limited, and thus
 +broadcast/​multicast delivery is the only viable solution operators see to
 +this obvious revenue-threatening bottleneck. ​ Examples of such commercial
 +standardization efforts include 3GPP MBMS, DVB-H IPDatacast, 3GPP2 BCMCS and
 +DMB. One of the primary challenges in using broadcast/​multicast channels for
 +delivering multimedia is to provide a reliable solution that efficiently
 +uses the channel. ​ For cellular unicast delivery, there are a number of
 +methods to assure reliability and efficiency, including automatic modulation
 +and error-correction adjustments at the physical layer, automatic
 +retransmission ​ of lost radio packets, and automatic adjustments of transmit
 +power, all based on continual feedback from each individual receiver.  ​
 +For   ​cellular broadcast/​multicast delivery, none of these methods are applicable, ​
 +and the primary method of providing reliability instead is the use of   ​application-layer ​
 +FEC codes. In this talk we describe some of the   ​broadcast/​multicast services to
 +be offered and specifically how   ​application-layer FEC codes provide reliability and
 +channel efficiency for   each of the services. ​ We also describe in some detail ​
 +Raptor R10, the   ​application-layer FEC code that has been chosen by 3GPP MBMS 
 +and DVB-H   ​IPDatacast,​ and that is under consideration in all of the remaining cellular
 +standards that have not yet made a selection.
 +{{:​en:​group:​seminars:​luby1005.pdf|Full presentation}}