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Methods and apparatus for improving accuracy of radio timing measurements

  • US 7,359,711 B2
  • Filed: 06/13/2003
  • Issued: 04/15/2008
  • Est. Priority Date: 10/31/2002
  • Status: Expired due to Fees
First Claim
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1. A method for improving the accuracy of a radio timing measurement made by a terminal, comprising:

  • making a first radio timing measurement for a radio transmission source at a time T*x according to a timing reference in said terminal;

    making a second radio timing measurement for said radio transmission source at a time T*y according to a timing reference in said terminal;

    determining a third radio timing measurement for said radio transmission source at a time T* according to a timing reference in said terminal based, at least in part, on said first radio timing measurement;

    determining a fourth radio timing measurement for said radio transmission source at said time T* based, at least in part, on said second radio timing measurement;

    determining a fifth radio timing measurement for said radio transmission source at said time T* based, at least in part, on said third radio timing measurement and said fourth radio timing measurement;

    making radio timing measurements for said radio transmission source at 2M (M≧

    1) sequential times T*1, T*2, . . . , T*2M according to a timing source in said terminal, wherein said making said first and second radio timing measurements for said radio transmission source at said respective times T*x and T*y is part of said making timing measurements for said radio transmission source at said 2M sequential times T*1, T*2, . . . , T*2M;

    determining a radio timing measurement for said radio transmission source at said time T* for each of said 2M timing measurements for said radio transmission source at said 2M sequential times; and

    determining a sixth radio timing measurement for said radio transmission source at said time T* based, at least in part, on said 2M radio timing measurements for said radio transmission source at said time T* determined from each of said 2M sequential radio timing measurements at times T*1, T*2, . . . , T*2M, wherein said determining a sixth radio timing measurement employs a weighted average of said 2M radio timing measurements for said radio transmission source at said time T* where the weight for any radio timing measurement at said time T* determined from a radio timing measurement at time T*i, (1≦

    i≦

    2M) is δ

    i/|T*−

    T*i| where δ

    i=−

    1 or δ

    i=+1, wherein T* exceeds each of the time values T*i, T*2, . . . , T*m and is less than each of the time values T*m+1, T*m+2, . . . , T*2M where 0≦

    m≦

    2M and δ

    i(1≦

    i≦

    2M) is chosen so that;

    δ

    i =+1 except as follows;

    if m<

    M;

    δ

    i=−

    1 for any (M−

    m) indices i in the range (m+1, m+2, . . . 2M) that give Σ

    (i=1 to i=2M) δ

    i/|T*i

    T*|≠

    0;

    if m>

    M;

    δ

    i=−

    1 for any (m−

    M) indices i in the range (1, 2, . . . m) that give Σ

    (i =1 to i=2M) δ

    i/|T*i

    T*|≠

    0;

    if m=M;

    all the values δ

    i are +1.

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