X. Y. WU ET AL.
Copyright © 2013 SciRes. CN
(a)
(b)
Figure 7. (a) Comparison for Delay CDF; (b) Comparison
for Fairness.
In the scheme CW of the node is adjusted dynamically
for the sake of adapting to the current network condition,
and AP skips the backoff phase by setting its backoff
counter as zero when non-AP STA completes transmis-
sion successfully to relieve the unfairness between chan-
nel access competition ability of AP and that of non-AP
STAs. Through the simulations, we verify the effective-
ness of our approach. The performances of both through-
put and mean end-to-end delay are improved effectively.
The unfairness is relieved to a large extent. Future re-
search will focus on how to satisfy hard QoS require-
ments and how different kinds of access networks such
as WLAN, LTE-A provide better services for users to-
gether.
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100 200 300400500 600
40
50
60
70
80
90
100
Mean End-to- End Del ay (ms)
Cumulative Fract ion (% )
EDCA
AEDCA
50 55 6065 70 7580
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
N um ber of St aions
Fairn es s be twee n Uplink a nd Downlink
EDCA
A-EDCA