Mobile station assisted forward link open loop power and rate control in a CDMA system

• US 20020187801A1
• Filed: 04/12/2002
• Published: 12/12/2002
• Est. Priority Date: 01/12/2000
• Status: Abandoned Application

• Current Assignee: Vieri Vanghi
• Original Assignee: Vieri Vanghi
• Inventors: Vanghi, Vieri
• Application Number:
  US10/121,975
• Publication Number:
  US 20020187801A1
• Time in Patent Office: Days
• US Class Current: 455/522
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 52/12 Outer and inner loops
• CPC Class Codes: H04W 52/143 Downlink power control
• CPC Class Codes: H04W 52/24 using SIR [Signal to Interference Ratio] or other wireless path parameters
• CPC Class Codes: H04W 52/26 using transmission rate or quality of service QoS [Quality of Service]
• CPC Class Codes: H04W 52/267 taking into account the information rate
• CPC Class Codes: H04W 52/34 TPC management, i.e. sharing limited amount of power among users or channels or data types, e.g. cell loading
• CPC Class Codes: H04W 52/40 during macro-diversity or soft handoff
• CPC Class Codes: H04W 52/50 at the moment of starting communication in a multiple access environment

Abstract

In a CDMA system, forward link load measurements and mobile station channel measurements are provided to the base station controller to allow the controller to jointly select the initial traffic channel transmit power and data rate. A mobile station reports a received pilot channel signal-to-noise ratio for all base stations in sight to a base station controller. The base stations report a current forward link load estimate to the base station controller. The base station controller sets a number of traffic channel connections and a traffic channel data rate to be allocated for the traffic channel connections, and sets a target traffic channel signal-to-noise ratio based on the data rate and the number of traffic channel connections. The initial traffic channel power is computed by the controller based on estimated forward link channel characteristics, the target traffic channel received signal-to-noise ratio, the base stations'"'"' load, the number of traffic channel connections, and the traffic channel data rate.

Claims

1. A CDMA wireless communications system that controls the initial power and data rate settings during forward link establishment of a traffic channel comprising:

a base station controller;

one or more base stations that report a current forward link load estimate to the base station controller; and

a mobile station that reports a received pilot channel signal-to-noise ratio to the base station controller,

wherein the base station controller sets the number of traffic channel connections and the data rate to be allocated for the traffic channel connections, computes a target traffic channel signal-to-noise ratio based on the data rate and the number of traffic channel connections, and computes the initial traffic channel power based on estimated forward link channel characteristics, the target traffic channel received signal-to-noise ratio, the base stations'"'"' load, the number of traffic channel connections, and the traffic channel data rate.

2. In a CDMA wireless communications system having a base station controller, one or more base stations, and a mobile station, a method for forward link open loop power and rate control comprising the following steps:

(a) the mobile station reports a received pilot channel signal-to-noise ratio for all base stations in sight to the base station controller;

(b) the base stations report a current forward link load estimate to the base station controller;

(c) the base station controller sets a number of traffic channel connections and a traffic channel data rate to be allocated for the traffic channel connections;

(d) the base station controller computes a target traffic channel signal-to-noise ratio based on the data rate and the number of traffic channel connections; and

(e) the base station controller computes the initial traffic channel power based on estimated forward link channel characteristics, the target traffic channel received signal-to-noise ratio, the base stations'"'"' load, the number of traffic channel connections, and the traffic channel data rate.

3. A method as claimed in claim 2, wherein in step (a), the base station controller first requests the mobile station to report the received pilot channel signal-to-noise ratio.

4. A method as claimed in claim 2, wherein in step (a), the mobile station autonomously reports the received pilot channel signal-to-noise ratio to the base station controller.

5. A method as claimed in claim 2, wherein in step (b), the base station controller interrogates the base stations for the current forward link load estimate.

6. A method as claimed in claim 2, wherein in step (e), the base station controller computes the initial traffic channel power as:

7. In a CDMA wireless communications system having a base station controller, one or more base stations, and a mobile station, a method for forward link power and rate control during hard handoff comprising the following steps:

(a) the mobile station searches for pilot signals on a target frequency and reports the strength of the pilot signals above a predetermined threshold to the base station controller, wherein the reported pilot signals form a requested target set;

(b) the base stations corresponding to the pilot signals in the requested target set report the current total transmit pilot channel signal-to-noise ratio;

(c) the base station controller sets a tentative granted set equal to the requested target set;

(d) the base station controller sets a target data rate to one in use by a connected service option;

(e) the base station controller sets the required traffic channels total signal-to-noise ratio to a predefined value based on the tentative granted set and the target data rate;

(f) the base station controller computes the required initial traffic channel power based on the tentative target set, the target data rate, the total transmit pilot channel signal-to-noise ratio and the required traffic channels total received signal-to-noise ratio;

(g) the base station controller determines whether a current base station residual capacity is above a desired threshold for the tentative granted set;

(h) if the residual capacity is above the desired threshold, the base station controller sets a granted set equal to the tentative granted set and commands the mobile station to initiate hard handoff; and

(i) if the residual capacity is below the desired threshold, the base station controller reduces the tentative granted set and the method returns to step (f).

8. A method as claimed in claim 7, wherein in step (b), the base station controller queries each base station for the current total transmit pilot channel signal-to-noise ratio.

9. A method as claimed in claim 7, wherein in step (f), the initial traffic channel power is computed as:

10. In a CDMA wireless communications system having a base station controller, one or more base stations, and a mobile station, a method for setting the data burst transmission rate on common control channels during soft handoff comprising the following steps:

(a) the base station controller receives a message to be delivered to the mobile station;

(b) the base station controller pages the mobile station on the primary common channels of a set of base stations that are serving the mobile station;

(c) the mobile station reports its current location and the strength of pilot signals above a predetermined threshold to the base station controller, wherein the reported pilot signals form a requested common control channels handoff set;

(d) the base stations corresponding to the pilot signals in the requested target set report the current total transmit pilot channel signal-to-noise ratio to the base station controller;

(e) the base station controller sets a tentative data rate equal to a maximum data rate;

(f) the base station controller sets the required common control channels total signal-to-noise ratio to a predefined value based on the tentative data rate and handoff set size;

(g) the base station controller computes the required common controls channel power based on the tentative data rate, the handoff set, the total transmit pilot channel signal-to-noise ratio and the required common control channels total received signal-to-noise ratio;

(h) the base station controller determines whether a current base station residual capacity is above a desired threshold for all base stations in the handoff set;

(i) if the residual capacity is above the desired threshold, the base station controller sets a granted data rate equal to the tentative data rate and transmits the message on secondary common control channels of the base station in the handoff set; and

(j) if the residual capacity is below the desired threshold, the base station controller sets the tentative data rate to the next lower supported data rate and the method returns to step (g).

11. A method as claimed in claim 10, wherein in step (d), the base station controller queries each base station for the current total transmit pilot channel signal-to-noise ratio.

12. A method as claimed in claim 10, wherein in step (g), the initial traffic channel power is computed as: