The following examples illustrate typical message exchanges between the mobile station and the base station during handoff. Refer to Annex B for examples of call processing during handoff.
Figure 2.6.6.3-1 shows an example of the messages exchanged between the mobile station and the base station during a typical handoff process if P_REV_IN_USEs is less than or equal to three or SOFT_SLOPEs is equal to ‘000000’.
Figure 2.6.6.3-2 shows an example of the messages exchanged between the mobile station and the base station during a typical handoff process if P_REV_IN_USEs is greater than three and SOFT_SLOPEs is not equal to ‘000000’.
Figure 2.6.6.3-3 illustrates the messaging triggered by a pilot of the Candidate Set as its strength gradually rises above the strength of each pilot of the Active Set if P_REV_IN_USEs is less than or equal to three, or SOFT_SLOPEs is equal to ‘000000’. Note that the mobile station reports that a Candidate Set pilot is stronger than an Active Set pilot only if the difference between their respective strengths is at least T_COMP 0.5 dB.
Figure 2.6.6.3-4 illustrates the messaging triggered by a pilot of the Candidate Set as its strength gradually rises above the strength of each pilot of the Active Set if P_REV_IN_USEs is greater than three and SOFT_SLOPEs is not equal to ‘000000’. Note that the mobile station reports that a Candidate Set pilot is stronger than an Active Set pilot only if the difference between their respective strengths is at least T_COMP 0.5 dB and Pilot P0 strength exceeds [(SOFT_SLOPE/8) ´ 10 ´ log10(PS1 + PS2) + ADD_INTERCEPT/2].
(1) Pilot strength exceeds T_ADD. Mobile station sends a Pilot Strength Measurement Message and transfers pilot to the Candidate Set.
(2) Base station sends an Extended Handoff Direction Message, a General Handoff Direction Message or a Universal Handoff Direction Message.
(3) Mobile station transfers pilot to the Active Set and sends a Handoff Completion Message.
(4) Pilot strength drops below T_DROP. Mobile station starts the handoff drop timer.
(5) Handoff drop timer expires. Mobile station sends a Pilot Strength Measurement Message.
(6) Base station sends an Extended Handoff Direction Message, a General Handoff Direction Message or a Universal Handoff Direction Message.
(7) Mobile station moves pilot from the Active Set to the Neighbor Set and sends a Handoff Completion Message.
Figure 2.6.6.3-1. Handoff Threshold Example if P_REV_IN_USEs is Less Than or Equal to Three, or SOFT_SLOPEs is Equal to ‘000000’
(1) Pilot P2 strength exceeds T_ADD. Mobile station transfers the pilot to the Candidate Set.
(2) Pilot P2 strength exceeds [(SOFT_SLOPE/8) ´ 10 ´ log10(PS1) + ADD_INTERCEPT/2]. Mobile station sends a Pilot Strength Measurement Message.
(3) Mobile station receives an Extended Handoff Direction Message, a General Handoff Direction Message or a Universal Handoff Direction Message, transfers the pilot P2 to the Active Set, and sends a Handoff Completion Message.
(4) Pilot P1 strength drops below [(SOFT_SLOPE/8) ´ 10 ´ log10(PS2) + DROP_INTERCEPT/2]. Mobile station starts the handoff drop timer.
(5) Handoff drop timer expires. Mobile station sends a Pilot Strength Measurement Message.
(6) Mobile station receives an Extended Handoff Direction Message, a General Handoff Direction Message or a Universal Handoff Direction Message, transfers the pilot P1 to the Candidate Set and sends a Handoff Completion Message.
(7) Pilot P1 strength drops below T_DROP. Mobile station starts the handoff drop timer.
(8) Handoff drop timer expires. Mobile station moves the pilot P1 from the Candidate Set to the Neighbor Set.
Figure 2.6.6.3-2. Handoff Threshold Example if P_REV_IN_USEs is Greater Than Three, and SOFT_SLOPEs is Not Equal to ‘000000’
Candidate Set: Pilot P0
Active Set: Pilots P1, P2
t0 – Pilot Strength Measurement Message sent, P0 > T_ADD
t1 – Pilot Strength Measurement Message sent, P0 > P1 + T_COMP 0.5 dB
t2 – Pilot Strength Measurement Message sent, P0 > P2 + T_COMP 0.5 dB
Figure 2.6.6.3-3. Pilot Strength Measurements Triggered by a Candidate Pilot if P_REV_IN_USEs = 3 or SOFT_SLOPEs = ‘000000’
Candidate Set: Pilot P0
Active Set: Pilots P1, P2
t0 – Pilot Strength Measurement Message not sent because
[10 ´ log10(PS0)] < [(SOFT_SLOPE/8) ´ 10 ´ log10(PS1 + PS2) + ADD_INTERCEPT/2]
t1 – Pilot Strength Measurement Message not sent because
P0 > [P1 + T_COMP 0.5 dB] but
[10 ´ log10(PS0)] < [(SOFT_SLOPE/8) ´ 10 ´ log10(PS1 + PS2) + ADD_INTERCEPT/2]
t1’ – Pilot Strength Measurement Message sent because
[10 ´ log10(PS0)] > [(SOFT_SLOPE/8) ´ 10 ´ log10(PS1 + PS2) + ADD_INTERCEPT/2]
t2 – Pilot Strength Measurement Message sent because
P0 > [P2 + T_COMP 0.5 dB] and
[10 ´ log10(PS0)] > [(SOFT_SLOPE/8) ´ 10 ´ log10(PS1 + PS2) + ADD_INTERCEPT/2]
Figure 2.6.6.3-4. Pilot Strength Measurements Triggered by a Candidate Pilot if P_REV_IN_USEs > 3 and SOFT_SLOPEs is Not Equal to‘000000’
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