Method and apparatus for time-division power assignments in a wireless communication system

• US 7,099,384 B1
• Filed: 09/01/2000
• Issued: 08/29/2006
• Est. Priority Date: 09/01/2000
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Agashe, Parag, Jalali, Ahmad, Smee, John
• Primary Examiner(s): Corrielus, Jean B.
• Application Number:
  US09/654,177
• Time in Patent Office: 2,188 Days
• Field of Search: 375/222, 375/262, 375/227, 375/224, 375/229, 375/232, 375/350, 375/225, 370/347, 342/383, 455/67.11, 455/63.1, 455/67.1, 455/226.1, 455/226.3, 455/296, 708/322, 708/323, 333/28.R, 333/18
• US Class Current: 375/229
• CPC Class Codes: H04B 7/005 Control of transmission; Equalising
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04W 52/343 taking into account loading or congestion level
• CPC Class Codes: H04W 52/40 during macro-diversity or soft handoff

Abstract

In a CDMA data communication system capable of variable rate data transmission, a time-division power assignment cyclically reduces the carrier power level to at least one sector to reduce interference in neighboring sectors. The base station determines a time-division power assignment for each sector and generates signals according to the power assignment. The mobile unit generates filter coefficients corresponding to each power level. The mobile unit estimates Carrier Signal-to-Interference (C/I) to determine a data rate for each power level. Previous iterations of the equalizer are stored and used to refine future estimates.

Claims

1. A mobile unit, comprising:

an antenna; and

an equalizer coupled to the antenna, the equalizer comprising;

a plurality of taps, each having first and second associated coefficients, the first associated coefficient corresponding to a first plurality of time slot occurrences, the second associated coefficient corresponding to a second plurality of time slot occurrences, time slot occurrences of the second plurality of time slot occurrences alternating with time slot occurrences of the first plurality of time slot occurrences, the plurality of taps being operative to scale a first set of input symbols during the first plurality of time slot occurrences by the first associated coefficients, the plurality of taps being further operative to scale a second set of input symbols during the second plurality of time slot occurrences by the second associated coefficients, the plurality of taps being further operative to generate tap outputs and being equal to a total number of symbols per sample set;

a summing node coupled to the plurality of taps, the summing node being operative to sum the tap outputs; and

a memory storage unit adapted to store coefficient adjustment information, wherein the associated coefficients are adjusted according to the coefficient adjustment information.

2. The mobile unit of claim 1, wherein the summing node is further operative to generate a carrier-to-interference ratio estimate for each time slot occurrence of the first and second pluralities of time slot occurrences.

3. The mobile unit of claim 2, further comprising:

a decision node operative to generate a data rate decision for said each time slot based on the carrier-to-interference ratio estimate generated for said each time slot occurrence.

4. The mobile unit of claim 3, wherein the decision node comprises a look-up table correlating carrier-to-interference ratio estimates and data rates.

5. An equalizer, comprising:

a plurality of taps being equal to a total number of symbols per sample set, the taps being operative to scale input symbols with a first set of associated coefficients during a first plurality of time slot occurrences and with a second set of associated coefficients during a second plurality of time slot occurrences, time slot occurrences of the second plurality of time slot occurrences alternating with time slot occurrences of the first plurality of time slot occurrences;

a coefficient adjustment node coupled to the plurality of taps, the coefficient adjustment node being operative to apply the first set of associated coefficients during the first plurality of time slot occurrences and to apply the second set of associated coefficients during the second plurality of time slot occurrences; and

a memory storage unit adapted to store coefficient adjustment information, wherein the associated coefficients are adjusted according to the coefficient adjustment information.

6. The equalizer of claim 5, wherein the equalizer is an adaptive equalizer.

7. The equalizer of claim 5, wherein the equalizer is configured to generate first carrier-to-interference ratio estimates for the first plurality of time slot occurrences and second carrier-to-interference ratio estimates for the second plurality of time slot occurrences.

8. The equalizer of claim 7, wherein at least some current first carrier-to-interference ratio estimates include historical information from previous time slots of the first plurality of time slot occurrences, and at least some current second carrier-to-interference ratio estimates include historical information from previous time slot occurrences of the second plurality of time slot occurrences, whereby equalization process for each time slot occurrence is continuous, proceeding from where the process ended during the previous corresponding time slot occurrence.

9. An adaptive equalizer, comprising:

a plurality of taps being equal to a total number of symbols per sample set, the taps being operative to scale input symbols with a first set of associated coefficients during a first time slot and with a second set of associated coefficients during a second time slot;

a coefficient adjustment node coupled to the plurality of taps, the coefficient adjustment node being operative to apply the first set of associated coefficients during the first time slot and to apply the second set of associated coefficients during the second time slot; and

a memory storage unit adapted to store coefficient adjustment information, wherein the associated coefficients are adjusted according to the coefficient adjustment information;

wherein the equalizer is operative to generate a carrier-to-interference ratio estimate, the equalizer having (2L+1) coefficients “

C”

, L being an integer greater than zero, the carrier-to-interference ratio estimate for a time slot “

i”

being given as;

$y_i<br><br>\left(n\right)=\underset{l=-L}{\overset{L}{\sum <br><br>}}<br><br><br><br>C_{i,l}<br><br>\left(n\right)·<br><br>x_i<br><br>\left(n-\mathrm{lT}\right)$

wherein “

n”

is a sample set index, each sample set comprising a plurality of input symbols, wherein “

x”

is an input symbol within a sample set, and wherein “

T”

is the period of the input symbol, x.

10. The equalizer of claim 9, further comprising:

a data rate decision node operative to receive the carrier-to-interference ratio estimate and determine a corresponding data rate.

11. A mobile unit, comprising:

an antenna; and

an equalizer coupled to the antenna, the equalizer comprising;

a plurality of taps,

a summing node coupled to the plurality of taps; and

a memory storage unit,

wherein each tap of the plurality of taps has associated coefficient values, the equalizer being configured to perform equalization process continuously for each time slot of at least two time slots, each time slot of the at least two time slots corresponding to a plurality of occurrences, coefficient values of said each time slot being stored at end of each occurrence of said each time slot and retrieved during the next occurrence of said each time slot, the plurality of taps being operative to scale a different set of input symbols during said each time slot by the coefficient values corresponding to said each time slot, the plurality of taps being further operative to generate tap outputs and being equal to a total number of symbols per sample set, the summing node being operative to sum the tap outputs, the memory storage unit being adapted to store coefficient adjustment information, wherein the associated coefficient values are adjusted according to the coefficient adjustment information.

12. An equalizer, comprising:

a plurality of taps;

a summing node coupled to the plurality of tans; and

a memory storage unit;

wherein each tap of the plurality of taps has associated coefficient values, the equalizer being configured to perform equalization process continuously for each time slot of at least two time slots, each time slot of the at least two time slots corresponding to a plurality of occurrences, occurrences of a first time slot of the at least two time slots alternating with occurrences of a second time slot of the at least two time slots, coefficient values of said each time slot being stored at end of each occurrence of said each time slot and retrieved during the next occurrence of said each time slot, the plurality of taps being operative to scale a different set of input symbols during said each time slot by the coefficient values corresponding to said each time slot, the plurality of taps being further operative to generate tap outputs and being equal to a total number of symbols per sample set, the summing node being operative to sum the tap outputs, the memory storage unit being adapted to store coefficient adjustment information, wherein the associated coefficient values are adjusted according to the coefficient adjustment information.