Method and apparatus for performing a candidate frequency search in a wireless communication system

A method of scheduling a candidate frequencies search in a wireless mobile station communication device (MS) operating on a sending frequency (SF) according to IS-95B (Interim Standard 95B) communicating with a base station (BS), the method comprising:

• (a) selecting a Max_Off_Time according to the maximum time the MS can operate off the SF while maintaining acceptable voice quality;
• (b) calculating time for searching for pilot signals (Tsw), where Tsw=Max_Off_Time−(2* Thw) and where Thw is defined as the time required by the MS to tune to a new frequency;
• (c) calculating the number of visits (Nv) to candidate frequencies during a freshness interval provided from the BS to the MS, and as defined by IS-95B;
• according to the equation Nv=Nm*Search_Size*Tm/Tsw, where:
• Search_Size is defined as a number representing pilot channels to be searched during a candidate frequencies search,
• Tm is defined as the time required to make one pilot measurement, and
• Tsw is defined as the time required by the mobile station to measure the strength of pilots on a candidate frequency during a visit to the candidate frequency,
• (d) calculating (voice quality) VQ according to the equation VQ=Nv*Max_Off_Time/(the freshness interval);
• (e) determining if VQ<Roff, where Roff is a pre-determined level of acceptable voice quality, and if VQ<Roff proceeding to step (g);
• (f) redefining Max_Off_Time and recalculating Tsw and Nv from:
• Max_Off_Time=Nm*Search_Size*Tm+2Thw,
• Tsw=Max_Off_Time−(2*Thw), and
• Nv=1;
• (g) calculating Nmpv and Tv from:
• Nmpv=Tsw/Tm
• Tv=(the freshness interval)/Nv;
• and
• (h) providing Nmpv, Tv and Nv to a search routine.