US 6,982,949 B2 | ||
Vertical roaming in wireless networks through improved wireless network cell boundary detection | ||
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 Feb. 28, 2003, as Appl. No. 10/376,881. | ||
Prior Publication US 2004/0170122 A1, Sep. 02, 2004 | ||
Int. Cl. H04J 11/00 (2006.01) |
U.S. Cl. 370—210 | 23 Claims |
1. A computer-implemented method of wireless network cell boundary detection, comprising:
periodically sampling wireless network signal strength received at an interface to a wireless network from a first cell of
the wireless network;
taking a Discrete Fourier Transform of the received signal strength samples;
determining that signal strength received at the interface to the wireless network is decreasing if an imaginary part of a
fundamental term of the Discrete Fourier Transform of the received signal strength samples is negative and less than a Fourier-domain
threshold; and
determining if a horizontal handoff to a second cell of the wireless network is pending.
|