| US 7,499,432 B2 | ||
| Vertical roaming in wireless networks through improved quality of service measures | ||
| Zihua Guo, Beijing (China); Qian Zhang, Beijing (China); Richard Yao, Morris Plains, N.J. (US); and Wenwu Zhu, Basking Ridge, N.J. (US) | ||
| Assigned to Microsoft Corporation, Redmond, Wash. (US) | ||
| Filed on Oct. 18, 2004, as Appl. No. 10/968,696. | ||
| Application 10/968696 is a division of application No. 10/377494, filed on Feb. 28, 2003, granted, now 6,944,144. | ||
| Prior Publication US 2005/0083874 A1, Apr. 21, 2005 | ||
| Int. Cl. H04Q 7/00 (2006.01); H04J 3/00 (2006.01); H04B 7/212 (2006.01); H04L 12/43 (2006.01) | ||
| U.S. Cl. 370—332 [370/345; 370/442; 370/459] | 13 Claims |
| 1. A computer-implemented method, comprising:
transmitting probing data packets from a mobile computing device in a wireless network, the probing data packets transmitted
in accordance with an IEEE 802.11 wireless network standard by a wireless network interface in compliance with a wireless
Network Driver Interface Specification;
calculating a probing data packet collision probability for the wireless network based upon the probing data packets, the
calculating comprising calculating a ratio of a number of unacknowledged probing data packets to a total number of probing
data packets transmitted, wherein the ratio is calculated by dividing a Network Driver Interface Specification Acknowledge
Failure Count statistic by the sum of the Network Driver Interface Specification Acknowledge Failure Count statistic and a
Transmitted Fragment Count statistic;
calculating a wireless network quality of service measure as a function of the probing data packet collision probability;
and
initiating a vertical handoff from a first type of wireless network to a second type of wireless network if the calculated
wireless network quality of service in the second type of wireless network is greater than observed wireless network quality
of service in the first type of wireless network.
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