−120 −100 −80 −60 −40 −20
Fig. 28. Packet Recovery for Severe Inter-Channel
Interference (Interference Power = -22dBm)
0 0.2 0.4 0.6 0.8 1
Cumulative Fraction (100%)
Proportion of Error Bits (100%)
Fig. 29. Portion of error bits of CRC-failed
N0 N1 N2 N3 N4 N5 N6
Fig. 30. Throughput Gain with 6 interfering
C. CCA Adjustment
To preserve the simplicity of our DCN, in this work, we sim-
ply ignore all the inter-channel interference and prohibit all the
co-channel interference. However, there is still much work to
do: 1) non-orthogonal design anyhow introduces inter-channel
interference, which might corrupt transmission in some cases.
Therefore, ignoring all the neighboring-channel interference is
unsafe. Future scheme should ﬁlter the neighboring-channel
interference which is intolerable to provide better transmis-
sion reliability; 2) current CCA-threshold is bounded by the
minimum power level of co-channel interference. Such setting
cannot leverage all the possible concurrencies and constrains
the relaxing gain. If some approach could differentiate the
current interference (i.e., identify it as co-channel interference
or not), then our DCN could leverage the inter-channel con-
currency and avoid co-channel collision at the same time. This
would be another direction of our future works.
In this paper, we propose a scheme DCN (Dynamic CCA-
threshold for Non-orthogonal transmission) for non-orthogonal
multi-channel design in WSNs. We observe that most
inter-interference generated from non-orthogonal neighboring-
channels is tolerable which indicates potential concurrent
transmissions between non-orthogonal channels. To capture
such concurrency opportunities, our DCN adjust the CCA-
threshold based on the recent records of interference. The
comprehensive experiments on our testbeds verify a signiﬁcant
throughput improvement of DCN comparing to the default
This research was supported in part by Supported
by Huawei-HKUST joint lab project, Hong Kong ITC
ITP/023/08LP, National Natural Science Foundation of China
Grant No. 60933012.
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