MIMO slotted aloha (MSA) system
First Claim
1. A method comprising:
- receiving at a synchronizing node a first reference frame from a first reference node at a first time and storing a first time value representing the first time;
calculating a timing estimator by subtracting a minimum time value, representing a distance from the synchronizing node to the first reference node, from the first time value;
receiving at the synchronizing node a second reference frame at a second time and storing a second time value representing the second time;
transmitting from the synchronizing node to the first reference node a short timing contention time frame;
receiving at the synchronizing node from the first reference node a first arrival time value representing a time at which the first reference node received the short timing contention frame;
calculating a first time drift from the first arrival time value and the second time value, wherein the first time drift equals;
(first arrival time value−
second time value)/2;
adjusting the timing estimator based on the first time drift; and
transmitting from the synchronizing node a frame according to a timing determined from the timing estimator.
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Abstract
A method including receiving at a synchronizing node a first reference frame from a first reference node at a first time and storing a first time value representing the first time, and calculating a timing estimator by subtracting a minimum time value, representing the distance from the synchronizing node to the first reference node, from the first time value. The method includes receiving at the synchronizing node a second reference frame at a second time and transmitting from the synchronizing node to the first reference node a short timing contention time frame. The method includes receiving at the synchronizing node from the first reference node an arrival time value representing the time at which the first reference node received the short timing contention frame and calculating a time drift from the first arrival time value and the second time value and adjusting the timing estimator based on the time drift.
16 Citations
12 Claims
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1. A method comprising:
- receiving at a synchronizing node a first reference frame from a first reference node at a first time and storing a first time value representing the first time;
calculating a timing estimator by subtracting a minimum time value, representing a distance from the synchronizing node to the first reference node, from the first time value;
receiving at the synchronizing node a second reference frame at a second time and storing a second time value representing the second time;
transmitting from the synchronizing node to the first reference node a short timing contention time frame;
receiving at the synchronizing node from the first reference node a first arrival time value representing a time at which the first reference node received the short timing contention frame;
calculating a first time drift from the first arrival time value and the second time value, wherein the first time drift equals;
(first arrival time value−
second time value)/2;
adjusting the timing estimator based on the first time drift; and
transmitting from the synchronizing node a frame according to a timing determined from the timing estimator. - View Dependent Claims (2, 3, 4, 5)
- receiving at a synchronizing node a first reference frame from a first reference node at a first time and storing a first time value representing the first time;
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6. A method comprising:
- receiving at a first node a plurality of frames from a plurality of reference nodes;
measuring and recording a first timing value for each of the plurality of frames, the first timing value representing arrival times of the plurality of frames;
transmitting a short time contention frame to the plurality of reference nodes;
receiving a second timing value from each of the plurality of reference nodes, the second timing value representing times of the respective reference nodes that received the short timing contention frames;
determining an average time drift for the arrival time values, wherein the time drift for each of the plurality of reference nodes equals;
(second timing value of the reference node−
first timing value of the reference node)/2;
adjusting a slot time of the first node according to the average time drift; and
transmitting data from the first node according to the adjusted slot time. - View Dependent Claims (7, 8, 9, 10, 11, 12)
- receiving at a first node a plurality of frames from a plurality of reference nodes;
Specification