Balancing the hidden and exposed node problems with power control in CSMA/CA-based wireless networks

Media Access Control (MAC) mechanism design is a key problem in wireless networking. One problem is hidden nodes, which are allowed to transmit, but which interfere with a receiver causing a collision. Another problem is exposed nodes, which are not allowed to transmit although they would not interfere, thus limiting spatial reuse. MAC designs like IEEE 802.11 [6] try to solve both of these problems, but are not wholly successful. Other MAC designs attempt to control the transmit power, both to lower power use and to minimize exposed nodes. This results in a worsened hidden node problem. We present a power control MAC that balances the hidden and exposed node problem. The idea is to use no more power than is needed to eliminate the hidden nodes, thus limiting the exposed nodes. We present simulation results that show our design out performs both 802.11 and previous power control MACs.