Improving Spatial Reuse through Tuning Transmit Power, Carrier Sense Threshold, and Data Rate in Multi-hop Wireless Networks. Tae-Suk Kim, Hyuk Lim, and Jennifer C. Hou Dept. of Computer Science UIUC ACM MobiCom 2006. the total number of concurrent transmissions - MAC layer.
Improving Spatial Reuse through Tuning Transmit Power, Carrier Sense Threshold, and Data Rate in Multi-hop Wireless Networks
Tae-Suk Kim, Hyuk Lim, and Jennifer C. Hou
Dept. of Computer Science
ACM MobiCom 2006
the total number
- MAC layer
the number of bits
that can be transported
simultaneously in the network
- PHY layer
Network Capacity in Ad-hoc Networks
- What is the optimal contending area?
- How does it relate to the transmit power and CS threshold?
Low rate links
High rate links
for Power Control
for CST tuning
How many power levels are needed to achieve the same control granularity as tuning the carrier sense threshold?
Increase the carrier sense range from D to D+ΔD such that one additional concurrent transmitter is included.
Interference level at Rx is decreased by ΔI
Number of power levels
For the better granularity,
In the case of D>>R,
Total of five levels should be sufficient!!!
Target Min Power level: Rx can sustain the minimum data rate.
Target CST level: Each node sets its carrier sense threshold s.t. if a transmitter transmits with Pmin at a distance R, the minimum data rate can be substained.
Conservative Scenario is assumed.
Minimum interference level perceived at TX
From the received signal strength level at Tx, the distance, L, to a hypothetical interfering node I is estimated.
The final Transmit Power
Unnecessarily high transmit power and CS Threshold not properly tuned can actually reduce the attainable level of spatial reuse !!!
 X. Yang and N. H. Vaidya. On the Physical Carrier Sense in Wireless Ad Hoc Networks. In Proceedings of IEEE INFOCOM, 2005.
 J. Fuemmeler, N. H. Vaidya, and V. V. Veeravalli. Selecting transmit powers and carrier sense thresholds for csma protocols. Technical Report, Univ. of Illinois at Urbana Champaign, 2004.
Thank You !