Data transmission in a wireless communication system
View Patent ↗A method and apparatus for transmitting a burst of data over a supplemental channel on just one leg of a handoff by changing the maximum allowed burst duration of the data to be transmitted over the supplemental channel as a function of the future and/or current characteristics of the communication link of the leg(s) of the handoff. The data is then transmitted over just one leg of handoff using the maximum allowed burst duration. By changing the parameters of the data, the data may still be acceptably received at the mobile terminal over just one leg of the soft handoff even when the strength of the pilot signal used for the supplemental channel changes significantly. In an illustrative embodiment of the invention the stability of the communication link is used as a way of ascertaining the future conditions of the communications link.
1. A method for use in a system where data is transmitted during a handoff, the handoff having at least two legs each being between a terminal and one of at least two sets of communication equipment, the method comprising the steps of:
responsive to a deterioration in at least one of the characteristics of a communication link that is part of at least one of the legs, changing the maximum allowed burst duration;
establishing a secondary channel over just one leg responsive to the maximum allowed burst duration being at least as large as a threshold burst duration; and
transmitting the data burst over the secondary channel.
2. The method of claim 1 , further comprising the step of responsive to the maximum allowed burst duration being smaller than the threshold burst duration transmitting the data burst over the primary channel.
3. The method of claim 1 , wherein:
each set of communication equipment includes a transmitter; and
the communication link is a forward link.
4. The method of claim 1 , wherein the characteristics of the communication link are obtained from a pilot strength measurement message.
5. The method of claim 1 , wherein the characteristics of the communication link are based on characteristics of at least one pilot signal, each of the sets of the communication equipment transmitting one of the at least one pilot signals.
6. The method of claim 5 , wherein the characteristics of the at least one pilot signal comprise whether an anchor set of the sets of communication equipment remains as the anchor set.
7. The method of claim 5 , wherein the characteristics of at least one pilot signal comprise a strength of a pilot signal of an anchor set of the sets of communication equipment for a first predetermined number of measurements.
8. The method of claim 1 , wherein the characteristics of the communication link are based on at least one of the following characteristics:
whether an anchor set of the sets of communication equipment remains as the anchor set;
a strength of a pilot signal of an anchor set of the sets of communication equipment for a first predetermined number of measurements;
the strength of the pilot signal of the anchor set of the sets communication equipment relative to a strength of a pilot signal of a non-anchor set of the sets of communication equipment;
the rate of change of the strength of the pilot signal of the anchor set of the sets of communication equipment; and
the rate of change of the strength of the pilot signal of the anchor set of the sets of communication equipment for a second predetermined number of measurements.
9. The method of claim 1 wherein the characteristics of the communication link are based on characteristics of a signal on a secondary channel.
10. A method for use in a system where a burst of data is transmitted during a handoff, the handoff having at least two legs each being between a terminal and one of at least two sets of communication equipment, the method comprising the steps of:
transmitting a first burst of data over just one of the legs using a first plurality of burst parameters;
responsive to a deterioration in at least one of the characteristics of a communication link that is part of at least one of the legs, selecting a second plurality of burst parameters where the maximum allowed burst duration of the second plurality is different from the first plurality of burst parameters;
establishing a secondary channel over just one leg responsive to the maximum allowed burst duration being at least as large as a threshold burst duration; and
transmitting the data burst over the secondary channel.
11. The method of claim 10 , further comprising the steps of responsive to the maximum allowed burst duration being smaller than the threshold burst duration transmitting the data burst over the primary channel.
12. The method of claim 10 , wherein:
each set of communication equipment includes a transmitter; and
the communication link is a forward link.
13. The method of claim 10 , wherein the characteristics of the communication link are obtained from a pilot strength measurement message.
14. The method of claim 10 , wherein the characteristics of the communication link are based on characteristics of at least one pilot signal, each of the sets of the communication equipment transmitting one of the at least one pilot signals.
15. The method of claim 14 , wherein the characteristics of the at least one pilot signal comprise whether an anchor set of the sets of communication equipment remains as the anchor set.
16. The method of claim 14 , wherein the characteristics of at least one pilot signal comprise a strength of a pilot signal of an anchor set of the sets of communication equipment for a first predetermined number of measurements.
17. The method of claim 10 , wherein the characteristics of the communication link are based on at least one of the following characteristics:
whether an anchor set of the sets of communication equipment remains as the anchor set;
a strength of a pilot signal of an anchor set of the sets of communication equipment for a first predetermined number of measurements;
the strength of the pilot signal of the anchor set of the sets communication equipment relative to a strength of a pilot signal of a non-anchor set of the sets of communication equipment;
the rate of change of the strength of the pilot signal of the anchor set of the sets of communication equipment; and
the rate of change of the strength of the pilot signal of the anchor set of the sets of communication equipment for a second predetermined number of measurements.
18. The method of claim 10 , wherein the characteristics of the communication link are based on characteristics of a signal on a secondary channel.
19. A method for use in a system where a burst of data is transmitted during a handoff, the handoff having at least two legs each being between a terminal and one of at least two sets of communication equipment, the method comprising the steps of:
determining a maximum allowed burst duration as a function of the characteristics of a communication link that is part of at least one of the legs;
establishing a secondary channel over just one leg responsive to the maximum allowed burst duration being at least as large as a threshold burst duration; and
transmitting the data burst over the secondary channel.
20. The method of claim 19 , further comprising the step of responsive to the maximum allowed burst duration being smaller than the threshold burst duration transmitting the data burst over the primary channel.
21. The method of claim 19 , wherein:
each set of communication equipment includes a transmitter; and
the communication link is a forward link.
22. The method of claim 19 , wherein the characteristics of the communication link are obtained from a pilot strength measurement message.
23. The method of claim 19 , wherein the characteristics of the communication link are based on characteristics of at least one pilot signal, each of the sets of the communication equipment transmitting one of the at least one pilot signals.
24. The method of claim 23 , wherein the characteristics of the at least one pilot signal comprise whether an anchor set of the sets of communication equipment remains as the anchor set.
25. The method of claim 23 , wherein the characteristics of at least one pilot signal comprise a strength of a pilot signal of an anchor set of the sets of communication equipment for a first predetermined number of measurements.
26. The method of claim 19 , wherein the characteristics of the communication link are based on at least one of the following characteristics:
whether an anchor set of the sets of communication equipment remains as the anchor set;
a strength of a pilot signal of an anchor set of the sets of communication equipment for a first predetermined number of measurements;
the strength of the pilot signal of the anchor set of the sets communication equipment relative to a strength of a pilot signal of a non-anchor set of the sets of communication equipment;
the rate of change of the strength of the pilot signal of the anchor set of the sets of communication equipment; and
the rate of change of the strength of the pilot signal of the anchor set of the sets of communication equipment for a second predetermined number of measurements.
27. The method of claim 19 , wherein the characteristics of the communication link are based on characteristics of a signal on a secondary channel.