Radio frequency signals are commonly used in the development of indoor localization\nsystems. The infrastructure of these systems includes some beacons placed at known positions that\nexchange radio packets with users to be located. When the system is implemented using wireless\nsensor networks, the wireless transceivers integrated in the network motes are usually based on the\nIEEE 802.15.4 standard. But, the CSMA-CA, which is the basis for the medium access protocols in\nthis category of communication systems, is not suitable when several users want to exchange bursts\nof radio packets with the same beacon to acquire the radio signal strength indicator (RSSI) values\nneeded in the location process. Therefore, new protocols are necessary to avoid the packet collisions\nthat appear when multiple users try to communicate with the same beacons. On the other hand,\nthe RSSI sampling process should be carried out very quickly because some systems cannot tolerate\na large delay in the location process. This is even more important when the RSSI sampling process\nincludes measures with different signal power levels or frequency channels. The principal objective\nof this work is to speed up the RSSI sampling process in indoor localization systems. To achieve\nthis objective, the main contribution is the proposal of a new MAC protocol that eliminates the\nmedium access contention periods and decreases the number of packet collisions to accelerate the\nRSSI collection process. Moreover, the protocol increases the overall network throughput taking\nadvantage of the frequency channel diversity. The presented results show the suitability of this\nprotocol for reducing the RSSI gathering delay and increasing the network throughput in simulated\nand real environments.
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