Media access control (mac) frame structure and data communication method in a real-time localization system

A method comprising:

• calculating, by a position estimator, a plurality of time differences between receiving a range request (REQ) packet transmitted by a mobile device and receiving a plurality of range response (RSP) packets transmitted by a plurality of anchors, wherein each of the RSP packets is in response to the REQ packet, wherein each of the plurality of anchors has a known location;
• and
• estimating, by the position estimator, a position of the mobile device according to the plurality of time differences,
• wherein each REQ packet and each RSP packet is communicated in accordance with a media access control (MAC) frame structure comprising:
• a beacon period for synchronizing the plurality of anchors via transmission of a first set of communication packets, a contention-free period, and a contention period, wherein the RSP packets are transmitted during the contention period, and wherein the plurality of anchors only transmit RSP packets in response to REQ packets transmitted during the contention period.

A system comprising:

• a plurality of anchors that each have a known location;
• a position estimator including a processing system having a processor;
• and
• a memory that stores executable instructions that, when executed by the processing system, facilitate performance of operations, the operations comprising:
• calculating a plurality of time differences for pairs of packets, wherein each time difference of the pairs of packets is between transmitting of a range request (REQ) packet and receiving of a range response (RSP) packet, wherein the REQ packet of each of the pairs is either transmitted by a mobile device or is transmitted by at least some of the plurality of anchors;
• and
• estimating a position of the mobile device according to the plurality of time differences,
• wherein each REQ packet and each RSP packet is communicated in accordance with a media access control (MAC) frame structure comprising:
• a beacon period for synchronizing the plurality of anchors via transmission of a first set of communication packets, a contention-free period and a contention period,
• wherein the REQ packets are transmitted during the contention period, and wherein RSP packets are transmitted only in response to the REQ packets transmitted during the contention period.