Wireless link simulation with generic caching

• US 20050048964A1
• Filed: 04/09/2004
• Published: 03/03/2005
• Est. Priority Date: 08/25/2003
• Status: Active Grant

• Current Assignee: Riverbed Technology, LLC (Riverbed Technology Incorporated)
• Original Assignee: OPNET Technologies Incorporated (Riverbed Technology Incorporated)
• Inventors: Cohen, Alain J., Gurevich, Yevgeny, Plun, Jerome
• Granted Patent: US 7,254,389 B2
• Time in Patent Office: Days
• US Class Current: 455/423
• CPC Class Codes: H04W 16/18 Network planning tools

Abstract

A simulation system includes a cache structure that stores determined characteristics related to the propagation of an event. If a similar event occurs, and the factors affecting the determination of these characteristics have not changed, the characteristics associated with the new event are retrieved from the cache, rather than being re-determined from the underlying factors. In the example of mobile transceivers, if multiple transceivers share a common set of underlying factors, the determined characteristics of one transceiver can be shared among all of the other transceivers. If the underlying factors are dependent upon geographic area, mobile transceivers that enter a geographic area having associated cached characteristics can use the cached characteristics of other transceivers that are, or had been, in the area. Because the cache process is structured to intercept a call to the routine that determines the characteristics, the modifications to a simulation system to incorporate this caching feature should be minimal.

Claims

1. A simulation system comprising:

an event handler that is configured to determine occurrences of events,

a node simulator that is configured to simulate each event to determine one or more characteristics associated with the occurrence of the event,

a cache that is configured to store the one or more characteristics associated with the occurrence of select events,

and

a cache controller that is configured to determine whether;

to invoke the node simulator to determine the one or more characteristics associated with a subsequent event or

to retrieve the one or more characteristics associated with the subsequent event from the cache.

2. The simulation system of claim 1, wherein

the select events correspond to communications from a transmitter to a receiver in a wireless network.

3. The simulation system of claim 2, wherein:

the cache controller is further configured to;

determine a transmitter cluster associated with the transmitter, determine a receiver cluster associated with the receiver; and

the cache is configured to store the one or more characteristics based on the transmitter cluster and the receiver cluster.

4. The simulation system of claim 3, wherein

the cache controller determines the transmitter cluster and the receiver cluster based upon factors associated with the event.

5. The simulation system of claim 3, wherein

the receiver cluster is determined based upon a location of the receiver relative to a location of the transmitter.

6. The simulation system of claim 3, wherein

the transmitter cluster is determined based upon an output power of the transmitter.

7. The simulation system of claim 1, wherein:

each event includes factors that influence the determination of the one or more characteristics, and

the cache is configured to store the one or more characteristics based on the factors.

8. The simulation system of claim 1, wherein:

each event includes factors that influence the determination of the one or more characteristics,

the cache controller is further configured to determine a category associated with the event based on the factors, and

the cache is configured to store the one or more characteristics based on the category.

9. The simulation system of claim 8, wherein

the cache controller determines the category based on a quantization of one or more of the factors.

10. The simulation system of claim 8, wherein

the cache controller determines the category based on a defined range of one or more of the factors.

11. A simulation method comprising:

determining an event to be simulated; and

if a similar event has been simulated previously;

retrieving characteristics associated with the similar event from a cache;

otherwise;

simulating the event to determine characteristics associated with the event, and

storing the characteristics associated with the event in the cache.

12. The simulation method of claim 11, wherein

determining whether the similar event has been previously simulated includes:

categorizing the event, and

determining whether a similarly categorized event has been previously simulated.

13. The simulation method of claim 12, wherein

categorizing the event includes quantizing one or more factors underlying the event.

14. The simulation method of claim 12, wherein

categorizing the event includes clustering components of the event.

15. The simulation method of claim 11, wherein

the event corresponds to a communication from a transmitter to a receiver;

and

determining whether the similar event has previously been simulated includes;

determining a transmitter cluster corresponding to the transmitter, and

determining a receiver cluster corresponding to the receiver; and

determining whether the characteristics are stored in the cache corresponding to a communication from the transmitter cluster and the receiver cluster.

16. The simulation method of claim 15, wherein

determining the transmitter cluster and the receiver cluster is based on one or more factors underlying the event.

17. The simulation method of claim 15, wherein

determining the transmitter cluster and the receiver cluster is based on one or more defined ranges of one or more factors underlying the event.

18. The simulation method of claim 15, wherein

determining the transmitter cluster is based on an output power of the transmitter.

19. The simulation method of claim 15, wherein

determining the receiver cluster is based on a location of the receiver relative to a location of the transmitter.

20. A computer program for execution on a computer system that causes the communication system to:

maintain a schedule of events to be simulated;

select an event from the schedule of events based on a simulated time;

determine whether the event is cache-related; and

,

if the event is not cache-related;

simulate the event to determine characteristics related to the event;

otherwise,

if the event is cache-related;

determine whether a similar event has previously been simulated; and

if the similar event has previously been simulated;

retrieve characteristics related to the similar event from a cache;

otherwise

simulate the event to determine characteristics related to the event, and store the characteristics related to the event in the cache; and

schedule subsequent events based on the characteristics.

21. The computer program of claim 20, wherein the computer is further configured to

determine whether the similar event has been previously simulated by:

categorizing the event, and

determining whether a similarly categorized event has been previously simulated.

22. The computer program of claim 21, wherein the computer is further configured to

categorize the event by quantizing one or more factors underlying the event.

23. The computer program of claim 21, wherein the computer is further configured to

categorize the event by clustering components of the event.

24. The computer program of claim 20, wherein:

the event corresponds to a communication from a transmitter to a receiver; and

the computer is further configured to;

determine whether the similar event has previously been simulated by;

determining a transmitter cluster corresponding to the transmitter, and

determining a receiver cluster corresponding to the receiver; and

determine whether the characteristics are stored in the cache corresponding to a communication from the transmitter cluster and the receiver cluster.

25. The computer program of claim 24, wherein the computer is further configured to

determine the transmitter cluster and the receiver cluster based on one or more factors underlying the event.

26. The computer program of claim 24, wherein the computer is further configured to

determine the transmitter cluster based on an output power of the transmitter.

27. The computer program of claim 24, wherein the computer is further configured to

determine the receiver cluster based on a location of the receiver relative to a location of the transmitter.