Method and apparatus for scheduling broadcast information
Methods and apparatus are disclosed for efficiently scheduling incoming information objects so that timely objects from a variety of content classes are scheduled for broadcast. The incoming information objects are preferably received from one or more information sources, and are tagged with attributes that associate each object with one or more classes of information (e.g., sports, news, etc.), and provide a gauge of the timeliness or ‘age’ of the object. The tags can be used to select and broadcast objects from a variety of classes, and to identify the most timely objects at any give time.
1. A method for delivering objects to one or more receiver units, comprising:
using a computer to perform the steps of:
receiving a number of incoming objects, each object corresponding to one or more classes;
maintaining objects from a variety of classes in an object schedule,
wherein each object has a utility factor comprising one or more of the importance of the object, the timeliness of the object, and the number of objects previously transmitted in a same or related class as the current object; and
delivering selected objects from the object schedule to the one or more receiver units,
wherein each class has a utility factor that is calculated by combining, via a sub-linear function, the utility factors of those scheduled objects that correspond to the class; and
wherein the sub-linear function includes a square-root function.
2. A method according to claim 1 , wherein objects from a variety of classes are maintained by determining which of the incoming objects are to be added to the object schedule and which of the cached objects in the object schedule are be evicted, such that objects from a variety of classes are maintained in the object schedule.
3. A method according to claim 1 , wherein each object has a utility factor, and the value of the utility factor is dependent, at least to some degree, on the position of the object in the object schedule.
4. A method according to claim 1 , wherein the object schedule has an overall schedule utility factor, the overall schedule utility factor is calculated by combining via a schedule function the utility factors for each of the classes.
5. A method according to claim 4 , wherein the schedule function is a summing function.
6. A method according to claim 4 , wherein objects from a variety of classes are maintained in the object schedule by:
receiving a new object;
scheduling the new object in an initial position within the object schedule; and
reordering the scheduled objects so that the overall schedule utility factor is increased.
7. A method according to claim 1 , wherein each object in the object schedule has an estimated time for delivery based on the position of the object in the schedule.
8. A method according to claim 7 , wherein each object in the schedule has an importance factor.
9. A method according to claim 8 , wherein the utility factor for each object is dependent on the estimated time for delivery and the importance factor.
10. A method according to claim 9 , wherein the value of the utility factor Utilityobj for each object is related to the importance factor of the object times a function f(AGE), where f(AGE) is a predetermined function that decreases with an AGE of the object, the AGE of the object being related to the estimated time for delivery.
11. A method according to claim 10 , wherein the value of the utility factor Utilityobj for each object is related to the importance factor of the object times a freshness function R(AGE), where R(AGE) is a predetermined function that decreases with an AGE of the object, the AGE of the object being related to the estimated time for delivery.
12. A method according to claim 1 , wherein each object in the schedule is a member of one or more classes, and the utility factor for each object is dependent on a ClassVarietyScore of each of the member classes.
13. A method according to claim 12 , wherein the ClassVarietyScore for each class is a measure of the number of member objects of the class that were previously broadcast and/or are scheduled to be broadcast.
14. A method according to claim 13 , wherein the contribution of each object to the ClassVarietyScore decreases with time.
15. A method according to claim 14 , wherein each class has a class importance factor.
16. A method according to claim 15 , wherein the utility factor Utilityobj for each object is the sum over all member classes, the class importance factor of each member class times a function g(ClassVarietyScore), where g(ClassVarietyScore) is a predetermined function that decreases with the ClassVarietyScore of the class.
17. A method for scheduling objects for delivery to one or more receiver units, the method comprising:
using a computer to perform the steps of:
receiving one or more incoming objects, each having a utility factor;
scheduling the objects for delivery in an initial scheduling order, the value of the utility factor for each of the objects being dependent, at least to some degree, on the position of the object in the schedule;
calculating an overall schedule utility factor for the schedule by combining the utility factors of each of the scheduled objects using a predefined function;
reordering the scheduled objects so that the overall schedule utility factor is increased, wherein reordering the scheduled objects includes:
moving a selected object up one position in the schedule;
calculating an updated overall schedule utility factor;
determining if the undated overall schedule utility factor is greater than the previous overall schedule utility factor; and
retaining the new position of the selected object if the undated overall schedule utility factor is greater than the previous overall schedule utility factor; and
delivering one or more of the objects from the top of the schedule.
18. A method according to claim 17 , further comprising:
repeating the moving, calculating, determining, and retaining steps until the updated overall schedule utility factor is not greater than the previous overall schedule utility factor; and
returning the selected object to its previous position when the updated overall schedule utility factor is not greater than the previous overall schedule utility factor.
19. A method according to claim 17 , wherein the utility factor of an object is higher than another similarly situated object if the object is more timely.
20. A method according to claim 17 , wherein the utility factor of an object increases the overall schedule utility factor more than another similarly situated object if the object provides more variety to the object schedule.
21. A method according to claim 17 , wherein each object in the schedule has an estimated time for delivery based on the position of the object in the schedule, and the value of the utility factor for the object is dependent on the estimated time for delivery.
22. A method according to claim 21 , wherein the estimated time for delivery of each object is calculated by:
estimating a current channel bandwidth for delivery of the scheduled objects; and
calculating an estimated time for delivery for each object using the size of each scheduled object and the estimated channel bandwidth.
23. A method according to claim 22 , wherein each object in the schedule is a member of one or more classes, and the value of the utility factor for each class is dependent on a measure of the objects assigned to the class.
24. A method according to claim 23 , wherein the measure of the objects is the number of objects assigned to the class.
25. A method according to claim 23 , wherein the measure of the objects is the number of object bytes assigned to the class.
26. A method according to claim 23 , wherein the measure of the objects is the sum of the object utility factors assigned to the class.
27. An information delivery system, comprising
a receiver for receiving a stream of incoming objects, each object corresponding to one or more classes;
object schedule for storing a set of the incoming objects, wherein each object has a utility factor comprising one or more of the importance of the object, the timeliness of the object, and the number of objects previously transmitted in a same or related class as the current object;
object scheduler for determining which of the incoming objects to add to the object schedule and which of the cached objects to evict from the object schedule, such that objects from a variety of classes are maintained in the object store; and
delivery means for delivering selected cached objects from the object schedule to one or more receiver units based on the position of the object in the object schedule,
wherein each class has a utility factor that is calculated by combining, via a sub-linear function, the utility factors of those scheduled objects that correspond to the class, and
wherein the sub-linear function includes a square-root function.
28. An information delivery system according to claim 27 , wherein each object has a utility factor, and the value of the utility factor is dependent, at least to some degree, on the position of the object in the object schedule.
29. An information delivery system according to claim 27 , wherein the object schedule has an overall schedule utility factor, the overall schedule utility factor is calculated by combining, via a schedule function, the utility factors for each of the classes.
30. An information delivery system according to claim 29 , wherein the schedule function is a summing function.
31. A method for scheduling objects for delivery to one or more receiver units, the method comprising:
using a computer to perform the steps of:
receiving one or more incoming objects, each having a utility factor;
scheduling the objects for delivery in an initial scheduling order, the value of the utility factor for each of the objects being dependent, at least to some degree, on the position of the object in the schedule;
calculating an overall schedule utility factor for the schedule by combining the utility factors of each of the scheduled objects using a predefined function;
reordering the scheduled objects so that the overall schedule utility factor is increased, wherein reordering the scheduled objects includes:
moving a selected object to a random position in the schedule;
calculating an updated overall schedule utility factor;
determining if the updated overall schedule utility factor is greater than the previous overall schedule utility factor; and
retaining the new position of the selected object if the updated overall schedule utility factor is greater than the previous overall schedule utility factor; and
delivering one or more of the objects from the top of the schedule.
32. A method according to claim 31 , further comprising:
repeating the moving, calculating, determining, and retaining steps until the updated overall schedule utility factor is not greater than the previous overall schedule utility factor; and
returning the selected object to its previous position when the updated overall schedule utility factor is not greater than the previous overall schedule utility factor.
33. A method according to claim 31 , further comprising:
selecting another object and moving the selected object to a random position in the schedule;
repeating the moving, calculating, determining, and retaining steps until the updated overall schedule utility factor is not greater than the previous overall schedule utility factor; and
returning the selected object to its previous position when the updated overall schedule utility factor is not greater than the previous overall schedule utility factor.