組合數學研討會
主講者: 1. 羅元勳 博士 (師範大學) 2. 陳聖華 先生 (台灣大學)
講題: 1. On Protocol Sequences with Multiple-Packet Reception: Throughput Invariance and User Irrepressibility 2. TBA
時間: 2014-04-11 (Fri.)  14:00 - 17:00
地點: 數學所 617 研討室 (台大院區)
Abstract: Protocol sequences are used for channel access in the collision channel without feedback. For each user, the transmission of packets follows a specific periodical zero-one pattern, called the protocol sequence. It is assumed that the channel has the ability of the multiple-packet reception (MRP), i.e., all packets in a collision can be received error-free whenever there are at most $\gamma$ involved packets. The fluctuation in throughput is incurred by random relative delay offsets among the beginning of protocol sequences due to the lack of feedback. In this talk we investigate a class of protocol sequences which have zero-variance throughput considering MPR. Such protocol sequences are said to be throughput-invariant (TI). \emph{Shift-invariant} (SI) sequences form an important class of protocol sequences which enjoy perfect crosscorrelation property. It was proved in [1] that they can produce zero-variance throughput for $\gamma=1$. In this talk we derived that SI sequences are indeed TI for any $\gamma$. And, it is shown that SI property is intrinsic for TI sequences in some cases. References: [1] K.W.Shum, C.S.Chen, C.W.Sung, and W.S.Wong, Shift-invariant protocol sequences for the collision channel without feedback,IEEE Trans. Inform. Theory, 55(7):3312--3322, Jul. 2009. [2] Y.Zhang, Y.-H.Lo, F.Shu, and W.S.Wong, Protocol sequences for multiple-packet reception, submitted. [3] Y.Zhang, Y.-H.Lo, F.Shu, and W.S.Wong, Protocol sequences for multiple-packet reception: throughput invariance and user irrepressibility,to appear in IEEE Int. Symp. Inform. Theory, Honolulu, Jun. 2014.
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