SSCH: Slotted Seeded Channel Hopping For Capacity Improvement in IEEE 802.11 Ad Hoc Wireless Networks


Capacity improvement is one of the principal challenges in wireless networking. We present a link-layer protocol called Slotted Seeded Channel Hopping, or SSCH, that increases the capacity of an IEEE 802.11 network by utilizing frequency diversity. SSCH can be implemented in software over an IEEE 802.11-compliant wireless card. Each node using SSCH switches across channels in such a manner that nodes desiring to communicate overlap, while disjoint communications do not overlap, and hence do not interfere with each other. To achieve this, SSCH uses a novel scheme for distributed rendezvous and synchronization. Simulation results show that SSCH significantly increases network capacity in several multi-hop and single-hop wireless networking scenarios.


Paramvir Bahl, Ranveer Chandra, and John Dunagan "SSCH: Slotted Seeded Channel Hopping for Capacity Improvement in IEEE 802.11 Ad-Hoc Wireless Networks", Mobicom, Philadelphia, September 2004.

We have simulated SSCH in QualNet, which is a scalable, packet-level network simulator. Due to proprietary concerns of QualNet, we are unable to put all the modified files for download. In our package we only included files we added, and the changes in the other files. We did not include the unchanged portion of the existing files. After downloading the files, unzip them, and follow the instructions in notes.txt to implement SSCH. Note that mac_802_11.c requires some careful modifications outlined in notes.txt.
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