CHAPTER 8 Impact of SPAM Game on Coding and Multi-User Interference

R E{#(n)#(n) + (8.1) and this last is one of the outcomes (known at the receiver side because also the receiver can perform the allocation) of the SPAM game. The other outcome of the SPAM game, that is, the throughput, gives to the transmitter the constellation cardinality for the number of symbols to be employed. So, the codes to be employed are a "set of codes" depending on the cardinality, linked to the capacity. For example, if a users achieve 1 bit/slot obviously the cardinality of possible symbols is 2, so only two symbols (BPSK-like) can be employed. On the other hand, if a user achieve a rate of 16 bit/slot, it can employ a constellation with 2 16 points (32K) with approximatively the same performance of the previous case. The system model is the above mentioned where learning, training, payload phase coexist. While about learning and training a lot of space is spent, here the focus is on the payload that can be summarized as #H -# # + -# d , (8.2) 276 wher

CHAPTER 9 Impact of SPAM Game on Upper Layers: Admissions Procedures, Routing and Pricing.

g learning phase) so it can proceed to subset the entire set into (i.e.) S subsets each containing a number n s ,1# n s N + 1 of mutually spatially interference-free nodes. In this way the access method provides a joint "space-time" procedure to access the medium. In fact, during a time slot, the nodes admitted to transmit are those belonging to the same subset. As an example, in Fig.9.1 it is supposed that, by considering 10 couples of transmit/receive nodes the BS (or AP) is able to detect statistical properties of interference and to divide the entire set in 4 subsets S 1 , S 2 , S 3 , S 4 defined as {1, 2, 4} {3, 8, 9} {6, 7} {5, 10} (9.1) so the temporal axis is divided by 4 di#erent time intervals, and, in example, during the first time slot (equal to T L + T tr + T pay ), only the users labelled as g=1,2,4 are "admitted" to transmit. Obviously with this approach all the N+1=10users are authorized to transmit but it is possible to anticipate here that, althoug