The queue output rate depends on the quality of the link (error probability
given in (6)) and the average number of retransmissions for each MSDU in the particular
link (given by (9) with the replacement of pi by li,j). If we assume that link li,j is shared
among multiple paths, then at the arrival of MSDU v at the queue of link li,j, another u
MSDUs (where, typically, 0 ?‰¤ u ?‰¤ v - 1) will be in the same queue. For each li,j, by
indicating the group of u MSDUs by vector vqueue(li,j), the queuing delay can be estimated
as:
( ) ( ) , ,
queue ,
mean max
queue ,
( )
( ) , i j i j i
i j
i j l w l
w l
d l d L t
??? ???
= ?¤ ??‘ p
v
. (11)
For the optimization of the routing strategy of each MSDU v (presented in the next
section), the determination of (11) can be performed dynamically during the path
estimation, under the knowledge of the previous decisions for the MSDUs that were
transmitted by the current node. Alternatively, each node can independently calculate (11)
based on the queue contents of the particular link and disseminate the result at frequent
intervals in the mesh network via the overlay infrastructure.
5.3 Problem Formulation
Assume a set of N wireless hops (nodes), with h1 being the video encoder (server) and hN
the video decoder (client), and a connectivity structure P with M paths, where each path i, 1
?‰¤ i ?‰¤ M consists of total
i ?? hops.
Pages:
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319