utilizing physical layer information to improve rfid tag

eceived. These tags will not enter the arbitrate state when they receive ACKs meant
for other tags.
Table 8.1 shows that the proposed algorithms show a 6.15%, 30% and 44.3% increase
Table 8.1. Performance of proposed algorithms
Algorithm Average identification time (us)
A (Base) 8711
B 8175
C 6106
D 4853
in the identification efficiency. The low increase in efficiency in the first algorithm
is partly due to the fixed frame sizes in the identification protocols. The latter two
algorithms show a significant performance increase compared to the base algorithm.
However this performance is expected to drop in practice due to the impact of ac-
curacy in signal separation. Nonetheless, modification of the present protocol can
be expected to give atleast another 10% performance benefit even by conservative
estimates.
The method described in section 6.3 can successfully used to improve the relia-
bility of an RFID reader. This ensures that none of the tags are missed in the iden-
tification process. This is of particular importance in application like store checkout
with multiple items in a shopping cart.
The simulation in section 6.4 shows the impact of the random number generator
on a tag which does not have a uniform distribution. The number of collisions when
two tags of the same type are within range is significantly higher than the case
when two different tags with different probability distribution functions are used.
Experiments done on real world tags however suggest close similarity to the uniform
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