TDM hand-off technique using time differences

Claim 2

In a radio frequency ("RF") communications system having a plurality of cells, each cell having a repeater for transmitting slots to and receiving slots from subscriber units located within the cell, each slot having a period T and including a marker, and wherein a predetermined subscriber unit in an assigned cell having an assigned repeater may be handed-off to a plurality of n adjacent cells having n adjacent repeaters, a method for handing-off the predetermined subscriber unit to an adjacent repeater, comprising the steps of, at the predetermined subscriber unit: (a) receiving a slot from each of the n adjacent repeaters, thus forming n received slots; (b) determining a quality value for each of the n received slots; (c) from the n received slots, selecting slots having a quality value≧a predetermined threshold, thus forming m selected slots with m corresponding adjacent repeaters, where m≦n; (d) receiving a slot from the assigned repeater; (e) for the m selected slots, determining the m arrival times of the corresponding m markers at the predetermined subscriber unit, and for the slot from the assigned repeater determining the arrival time t 0 of the corresponding marker from the assigned repeater; (f) determining when at least one adjacent repeater of the m adjacent repeaters is closer to the predetermined subscriber unit than the assigned repeater, based on the m arrival times of the m markers, and based on the arrival time t 0 of the marker from the assigned repeater; (g) determining when only one adjacent repeater of the plurality of n adjacent repeaters is closer to the predetermined subscriber unit than the assigned repeater; and, (h) handing-off to the adjacent repeater determined in step (g).

Claim 3

The method of claim 1, where the step (e) includes a step of averaging t 0 and the m arrival times of the m markers over time.

Claim 4

The method of claim 1, where step (b) includes a step of measuring the received signal strength.

Claim 5

The method of claim 1, where step (b) includes a step of measuring the bit error rate.

Claim 6

The method of claim 1, where step (b) includes a step of averaging the quality value over time.

Claim 7

The method of claim 1, where the RF communications system utilizes time division multiplexing ("TDM") frames.

Claim 8

In a radio frequency ("RF") communications system having a plurality of cells, each cell having a repeater for transmitting slots to and receiving slots from subscriber units located within the cell, each slot having a period T and including a marker, and wherein a predetermined subscriber unit in an assigned cell having an assigned repeater may be handed-off to a plurality of n adjacent cells having n adjacent repeaters, a method for handing-off the predetermined subscriber unit to an adjacent repeater, comprising the steps of, at the predetermined subscriber unit: (a) receiving a slot from each of the n adjacent repeaters, thus forming n received slots; (b) determining a quality value for each of the n received slots; (c) from the n received slots, selecting slots having a quality value≧a predetermined threshold, thus forming m selected slots with m corresponding adjacent repeaters, where m≦n; (d) receiving a slot from the assigned repeater; (e) for the m selected slots, determining the m arrival times of the corresponding m markers at the predetermined subscriber unit, and for the slot from the assigned repeater determining the arrival time t 0 of the corresponding marker from the assigned repeater; (f) determining when at least one adjacent repeater of the m adjacent repeaters is closer to the predetermined subscriber unit than the assigned repeater, based on the m arrival times of the m markers, and based on the arrival time t 0 of the marker from the assigned repeater; (g) determining when a plurality of adjacent repeaters of the n adjacent repeaters is closer to the predetermined subscriber unit than the assigned repeater; (h) determining the adjacent repeater of the plurality of adjacent repeaters as in step (g) that is closest to the predetermined subscriber unit, based on the m arrival times of the m markers; and, (i) handing-off to the adjacent repeater determined in step (h).

Claim 9

In a radio frequency ("RF") communications system having a plurality of cells, each cell having a repeater for transmitting slots to and receiving slots from subscriber units located within the cell, each slot having a period T and including a marker, and wherein a predetermined subscriber unit in an assigned cell having an assigned repeater may be handed-off to a plurality of n adjacent cells having n adjacent repeaters, a method for handing-off the predetermined subscriber unit to an adjacent repeater, comprising the steps of, at the predetermined subscriber unit: (a) receiving a slot from each of the n adjacent repeaters, thus forming n received slots; (b) determining a quality value for each of the n received slots; (c) from the n received slots, selecting slots having a quality value≧a predetermined threshold, thus forming m selected slots with m corresponding adjacent repeaters, where m≦n; (d) receiving a slot from the assigned repeater; (e) for the m selected slots, determining the m arrival times of the corresponding m markers at the predetermined subscriber unit, and for the slot from the assigned repeater determining the arrival time t 0 of the corresponding marker from the assigned repeater; (f) determining when at least one adjacent repeater of the m adjacent repeaters is closer to the predetermined subscriber unit than the assigned repeater, based on the m arrival times of the m markers, and based on the arrival time t 0 of the marker from the assigned repeater; (g) determining when a plurality of adjacent repeaters of the n adjacent repeaters is closer to the predetermined subscriber unit than the assigned repeater; (h) determining the adjacent repeater of the plurality of adjacent repeaters as in step (g) that is closest to the predetermined subscriber unit, based on the m arrival times of the m markers; and, (i) handing-off to the adjacent repeater determined in step (h).

Claim 10

In a radio frequency ("RF") communications system having a plurality of cells, each cell having a repeater for transmitting slots to and receiving slots from subscriber units located within the cell, each slot having a period T and including a marker, and wherein a predetermined subscriber unit in an assigned cell having an assigned repeater may be handed-off to a plurality of n adjacent cells having n adjacent repeaters, a method for handling-off the predetermined subscriber unit to an adjacent repeater, comprising the steps of, at the predetermined subscriber unit: (a) receiving a slot from each of the n adjacent, thus forming n received slots; (b) determining a quality value for each of the n received slots; (c) from the n received slots, selecting slots having a quality value≧a predetermined threshold, thus forming m selected slots with m corresponding adjacent repeaters, where m≦n; (d) receiving at least one slot from the assigned repeater; (e) for the m selected slots, determing the m arrival times of the corresponding m markers at the predetermined subscriber unit, and for the slot from the assigned repeater determining the arrival time t 0 of the corresponding marker from the assigned repeater; (f) determining the adjacent repeater of the m adjacent repeaters that is closest to the predetermined subscriber unit, based on the m arrival times of the m markers, and based on the arrival time t 0 of the marker from the assigned repeater; and, (g) handing-off to the adjacent repeater determined in step (f).

Claim 11

In a radio frequency ("RF") communications system having a plurality of cells, each cell having a repeater for transmitting slots to and receiving slots from subscriber units located within the cell, each slot having a period T and including a marker, and wherein a predetermined subscriber unit in an assigned cell having an assigned repeater may be handed-off to a plurality of n adjacent cells having n adjacent repeaters, a method for handling-off the predetermined subscriber unit to an adjacent repeater, comprising the steps of, at the predetermined subscriber unit: (a) receiving a slot from each of the n adjacent, thus forming n received slots; (b) determining a quality value for each of the n received slots; (c) from the n received slots, selecting slots having a quality value≧a predetermined threshold, thus forming m selected slots with m corresponding adjacent repeaters, where m≦n; (d) receiving at least one slot from the assigned repeater; (e) for the m selected slots, determing the m arrival times of the corresponding m markers at the predetermined subscriber unit, and for the slot from the assigned repeater determining the arrival time t 0 of the corresponding marker from the assigned repeater; (f) determining the adjacent repeater of the m adjacent repeaters that is closest to the predetermined subscriber unit, based on the m arrival times of the m markers, and based on the arrival time t 0 of the marker from the assigned repeater; and, (g) handing-off to the adjacent repeater determined in step (f).

Claim 12

The method of claim 8, where the step (d) includes a step of averaging t 0 and the m arrival times of the corresponding m markers over time.

Claim 13

The method of claim 8, where step (b) includes a step of measuring the received signal strength.

Claim 14

The method of claim 8, where step (b) includes a step of measuring the bit error rate.

Claim 15

The method of claim 8, where step (b) includes a step of detecting error detection bits.

Claim 16

The method of claim 8, where step (b) includes a step of averaging the quality value over time.

Claim 17

The method of claim 8, where the RF communication system utilizes time division multiplexing ("TDM") frames.

Claim 18

In a radio frequency ("RF") communications system having a plurality of cells, each cell having a repeater for transmitting slots to and receiving slots from subscriber units located within the cell, each slot having a period T and including a marker, and wherein a predetermined subscriber unit in an assigned cell having an assigned repeater may be handed-off to a plurality of n adjacent cells having n adjacent repeaters, a method for handing-off the predetermined subscriber unit to an adjacent repeater, comprising the steps of, at the predetermined subscriber unit: (a) receiving a slot from each of the n adjacent repeaters, thus forming n received slots; (b) receiving a slot from the assigned repeater; (c) for the n received slots determining the n arrival times of the corresponding n markers at the predetermined subscriber unit, and for the slot from the assigned repeater determining the arrival time t 0 of the corresponding marker from the assigned repeater; (d) determining the adjacent repeater that is closest to the predetermined subscriber unit, based on the n arrival times of the n markers, and based on the arrival time t 0 of the marker from the assigned repeater; and, (e) handing-off to the adjacent repeater determined in step (d).

Claim 19

In a radio frequency ("RF") communications system having a plurality of cells, each cell having a repeater for transmitting slots to and receiving slots from subscriber units located within the cell, each slot having a period T and including a marker, and wherein a predetermined subscriber unit in an assigned cell having an assigned repeater may be handed-off to a plurality of n adjacent cells having n adjacent repeaters, a method for handing-off the predetermined subscriber unit to an adjacent repeater, comprising the steps of, at the predetermined subscriber unit: (a) receiving a slot from each of the n adjacent repeaters, thus forming n received slots; (b) receiving a slot from the assigned repeater; (c) for the n received slots determining the n arrival times of the corresponding n markers at the predetermined subscriber unit, and for the slot from the assigned repeater determining the arrival time t 0 of the corresponding marker from the assigned repeater; (d) determining the adjacent repeater that is closest to the predetermined subscriber unit, based on the n arrival times of the n markers, and based on the arrival time t 0 of the marker from the assigned repeater; and, (e) handing-off to the adjacent repeater determined in step (d).

Claim 20

The method of claim 15, wherein the step (c) includes a step of averaging t 0 and the n arrival times of the n markers over time.

Claim 21

The method of claim 15, where the RF communication system utilizes time division multiplexing ("TDM") frames.