Performance evaluation of multicarrier channels

US 20030105997A1
Filed: 12/20/2000
Published: 06/05/2003
Est. Priority Date: 10/12/2000
Status: Active Grant

First Claim

Patent Images

1. A method of determining an uncoded bit error rate p_bbased on a target symbol error rate ε

_s, comprising;

determining the uncoded bit error rate p_bbased on a weighted series expansion of the target symbol error rate ε

_s, comprising weights W that are a function of a maximum number of symbol errors that can be corrected t and a number of symbols in an information field K; and

selecting the maximum number of symbol errors t and the number of symbols in the information field K such that the uncoded bit error rate p_bthat produces a symbol error rate that is less than or equal to the target symbol error rate ε

_sis largest.

View all claims

5 Assignments

Timeline View

Assignment View

0 Petitions

Accused Products

Abstract

A method and apparatus determines an uncoded bit error rate p_bbased on a target symbol error rate ε_s. The uncoded bit error rate p_bis determined based on a weighted series expansion of the target symbol error rate ε_s, comprising weights W that are a function of a maximum number of symbol errors that can be corrected t and a number of symbols in an information field K. The maximum number of symbol errors t and the number of symbols in the information field K is selected such that the uncoded bit error rate p_bthat produces a symbol error rate that is less than or equal to the target symbol error rate ε_sis largest.

67 Citations

View as Search Results

65 Claims

1. A method of determining an uncoded bit error rate p_bbased on a target symbol error rate ε
- _s, comprising;
  
  determining the uncoded bit error rate p_bbased on a weighted series expansion of the target symbol error rate ε
  
  _s, comprising weights W that are a function of a maximum number of symbol errors that can be corrected t and a number of symbols in an information field K; and
  
  selecting the maximum number of symbol errors t and the number of symbols in the information field K such that the uncoded bit error rate p_bthat produces a symbol error rate that is less than or equal to the target symbol error rate ε
  
  _sis largest.
- View Dependent Claims (2, 3, 4)
- - 2. The method of claim 1 wherein the weighted series expansion comprises at least a first term, wherein second order and higher terms are ignored to determine the uncoded bit error rate p_b.
  - 3. The method of claim 1 wherein the symbols comprise Reed-Solomon symbols.
  - 4. The method of claim 1 wherein the weighted series expansion to determine the uncoded bit error p_brate comprises the following relationship:

5. A method of determining an optimum bit load per subchannel in a multicarrier system with forward error correction, comprising:
- computing one or more values of a maximum number of symbol errors that can be corrected t, and a number of symbols in the information field K to determine the optimum bit load per subchannel in accordance with the following relationship;
  
  $1 - {(1 - W (t, K) ɛ_{S}^{\frac{1}{t + 1}})}^{1 / α} = ω (b) (1 - 2^{- b_{i} (t, K) / 2}) erfc (\sqrt{3 \cdot 10^{γ_{i} / 10} / (2^{b_{i} (t, K) + 1} - 2)}) \times [2 - (1 - 2^{- b_{i} (t, K) / 2}) erfc (\sqrt{3 \cdot 10^{γ_{i} / 10} / (2^{b_{i} (t, K) + 1} - 2)})]$ $wherein W (t, K) = {[(\begin{matrix} K + C + R - 1 \\ t \end{matrix})]}^{- \frac{1}{(t + 1)}}, ω (b) = \frac{1}{b \cdot 2^{b}} \sum_{i = 1}^{2^{b}} \sum_{j \neq i}^{χ_{i}} \frac{d_{H} (a_{i}, a_{j})}{χ_{i}},$ ε
  
  _srepresents a target symbol error rate, C+R represents a number of symbols in an error correction field, b represents a number of bit positions of a quadrature-amplitude-modulation symbol, ω
  
  (b) represents an average fraction of erroneous bits in an erroneous b-sized quadrature-amplitude-modulation symbol, a_irepresents a label for the i^thpoint of a constellation associated with a subchannel, a_jrepresents a label for the j^thpoint of a constellation associated with a subchannel, χ
  
  _irepresents a coordination number of the a_i^thpoint, d_H(a_i,a_j) represents a Hammning distance between respective binary vectors associated with points a_iand a_j; and
  
  selecting the maximum number of symbol errors that can be corrected t, and the number of symbols in the information field K such that the uncoded bit error rate p_bthat produces a symbol error rate that is less than or equal to the target symbol error rate is increased.

6. A method of determining an optimum bit load per subchannel in a multicarrier system with forward error correction, comprising:
- computing one or more values of a maximum number of symbol errors that can be corrected t, and a number of symbols in the information field K to determine the optimum bit load per subchannel in accordance with the following relationship;
  
  $1 - {(1 - W (t, K) ɛ_{S}^{\frac{1}{t + 1}})}^{1 / α} = ω (b) (1 - 2^{- b_{i} (t, K) / 2}) erfc (\sqrt{3 \cdot 10^{γ_{i} / 10} / (2^{b_{i} (t, K) + 1} - 2)}) \times [2 - (1 - 2^{- b_{i} (t, K) / 2}) erfc (\sqrt{3 \cdot 10^{γ_{i} / 10} / (2^{b_{i} (t, K) + 1} - 2)})], wherein W (t, K) = {[(\begin{matrix} K + C + R - 1 \\ t \end{matrix})]}^{- \frac{1}{(t + 1)}},$ ε
  
  _srepresents a target symbol error rate, C+R represents a number of symbols in an error correction field, b represents a number of bit positions of a quadrature-amplitude-modulation symbol, ω
  
  (b) represents an approximate average fraction of erroneous bits in an erroneous b-sized quadrature-amplitude-modulation symbol; and
  
  selecting the maximum number of symbol errors that can be corrected t, and the number of symbols in the information field K such that the uncoded bit error rate p_bthat produces a symbol error rate that is less than or equal to the target symbol error rate is increased.
- View Dependent Claims (7)
- - 7. The method of claim 6 wherein ω
    - (b_i) is determined in accordance with the following relationship;

8. A method of selecting forward error correction parameters in a channel having a plurality of subchannels in a multicarrier communications system, comprising:
- determining a signal-to-noise ratio representing a subset of the subchannels; and
  
  selecting forward error correction parameters of the channel based on the signal-to-noise ratio.
- View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17)
- - 9. The method of claim 8 wherein the subset of the subchannels comprises all of the subchannels of the channel.
  - 10. The method of claim 8 wherein the forward error correction parameters are utilized in Reed-Solomon encoding.
  - 11. The method of claim 8 wherein the signal-to-noise ratio is an average signal-to-noise ratio of respective signal-to-noise ratios of the subset of the subchannels.
  - 12. The method of claim 8 wherein the signal-to-noise ratio represents all of the subchannels.
  - 13. The method of claim 8 wherein the selecting comprises applying a mean field approximation to evaluate a bit load over the subset of subchannels.
  - 14. The method of claim 13 wherein the selecting comprises adjusting the mean field approximation.
  - 15. The method of claim 14 wherein the adjusting is applied when the number of bits per subchannel is less than or equal to two.
  - 16. The method of claim 14 wherein the adjusting is a linear adjustment with respect to a bit load of a subchannel.
  - 17. The method of claim 8 further comprising:
    - determining the representative performance measurement as an average signal-to-noise ratio γ
      
      _efffor the channel in accordance with the following relationship;
      
      $γ_{eff} = \frac{1}{n_{eff}} \sum_{γ_{i} > γ_{*}} γ_{i}, wherein n_{eff} = \sum_{γ_{i} > γ_{*}} 1,$ γ
      
      _irepresents a signal-to-noise measurement for an i^thsubchannel, and n_effrepresents a number of subchannels for which the signal-to-noise ratio γ
      
      _lwas measured for which γ
      
      _iis greater than γ
      
      *, and γ
      
      * represents a threshold signal-to-noise ratio.

18. A method of determining a bit load b per subchannel in a multicarrier system with forward error correction, comprising:
- computing one or more values of a maximum number of symbol errors that can be corrected t, and a number of symbols in the information field K to determine the bit load per subchannel in accordance with the following relationship;
  
  b=[γ
  
  +Φ
  
  (γ
  
  ,t,K,ε
  
  )]/10 log 2 , wherein $Φ (γ, t, K, ɛ) = 10 \log {10^{- γ / 10} + \frac{3 \log e}{\begin{matrix} 2 \log [\frac{α 〈 ω (b) 〉 \sqrt{8 / π}}{W (t, K) {(α ɛ / β)}^{\frac{1}{(t + 1)}}}] - \\ \log \log [\frac{α 〈 ω (b) 〉 \sqrt{8 / π}}{W (t, K) {(α ɛ / β)}^{\frac{1}{(t + 1)}}}] + \\ \log (\frac{\log e}{2}) \end{matrix}}}, W (t, K) = {{[(\begin{matrix} K + C + R - 1 \\ t \end{matrix})]}^{- \frac{1}{(t + 1)}} [(\begin{matrix} K + C + R \\ t + 1 \end{matrix})]}^{- \frac{k - 1}{(t + 1)}}, 〈 ω (b) 〉 = \frac{1}{b_{\max}} \int_{1}^{b_{\max}} ω (b) (1 - 2^{- b / 2}) \partial b$ α
  
  represents a number of bits per symbol, γ
  
  represents a signal-to-noise ratio, t represents a maximum number of symbol errors that can be corrected, ε
  
  represents a target bit error rate, C+R represents a number of symbols in an error correction field, b represents a number of bit positions of a quadrature-amplitude-modulation symbol, ω
  
  (b) represents an average fraction of erroneous bits in an erroneous b-sized quadrature-amplitude-modulation symbol, b_maxis a maximum bit load per subchannel; and
  
  selecting a bit load per subchannel in accordance with the maximum number of symbol errors that can be corrected t, and a number of symbols in the information field K.
- View Dependent Claims (19, 20)
- - 19. The method of claim 18 wherein Φ
    - (γ
      
      ,t,K,ε
      
      ) is evaluated at γ
      
      equals −
      
      ∞
      
      .
  - 20. The method of claim 18 wherein b is greater than or equal to three.

21. A method of selecting forward error correction parameters for use in a channel having a plurality of subchannels, comprising:
- determining an average signal-to-noise ratio of at least a subset of the subchannels; and
  
  selecting forward error correction parameters based on the average signal-to-noise ratio, and a count of the number of subchannels in the subset.
- View Dependent Claims (22, 23)
- - 22. The method of claim 21 wherein the selecting the forward error correction parameters comprises selecting the forward error correction parameters based on a predicted gain from application of the selected forward error correction parameters.
  - 23. The method of claim 22 wherein the gain is a performance gain.

24. A method of selecting at least one forward error correction parameter, comprising:
- computing one or more values representing a number of information symbols K in a frame accordance with the following relationship;
  
  $[\frac{α (K + s + zs)}{s n_{eff}} + 1.5] [1 - {(1 - ({[(\begin{matrix} K + C + R - 1 \\ t \end{matrix})]}^{- \frac{1}{(t + 1)}}) ɛ_{S}^{1 / (t + 1)})}^{1 / α}] = 2 (1 - 2^{\frac{α (K + s + zs)}{2 {sn}_{eff}}}) erfc (\sqrt{1.5 \cdot 10^{γ_{eff} / 10} / (2^{\frac{α (K + s + zs)}{{sn}_{eff}}} - 1)}) \times [2 - (1 - 2^{\frac{α (K + s + zs)}{2 {sn}_{eff}}}) erfc (\sqrt{1.5 \cdot 10^{γ_{eff} / 10} / (2^{\frac{α (K + s + zs)}{{sn}_{eff}}} - 1)})]$ $wherein t = ⌊ \frac{sz + 1 + e_{r}}{2} ⌋, e_{r} \leq sz, and$ s represents a number of discrete multi-tone symbols in a frame, z represents a number of error correction symbols in a discrete multi-tone symbol, α
  
  represents a number of bits per code symbol, C+R represents a number of redundant symbols in an error correction field, n_effrepresents a number of subchannels exceeding a threshold performance value, γ
  
  _effrepresents an effective signal-to-noise ratio associated with the number of subchannels exceeding the threshold performance value, ε
  
  _srepresents a target symbol error rate; and
  
  ε
  
  _rrepresents a number of erasures; and
  
  determining a number of bits per subchannel in accordance with the one or more values of K.
- View Dependent Claims (25, 26, 27)
- - 25. The method of claim 24 wherein K is a continuous variable.
  - 26. The method of claim 24 wherein K is computed using dichotomy, for values of γ
    - _eff, n_eff, z, and s.
  - 27. The method of claim 24 further comprising:
    - determining a net coding gain associated with values of γ
      
      _eff, n_eff, z, and s;
      
      determining an incremental number of bits per subchannel associated with the net coding gain; and
      
      storing associated values of γ
      
      _eff, n_eff, z, s and the incremental number of bits per subchannel.

28. A method of selecting transmission parameters of a multicarrier system having a channel comprising a plurality of subchannels, comprising:
- selecting a number (s) of discrete multi-tone symbols in a forward-error-correction frame, and a number (z) of forward-error-correction control symbols in a discrete multitone symbol based on a signal-to-noise ratio and a number of subchannels associated with the signal-to-noise ratio; and
  
  transmitting information in accordance with the selected number (s) of discrete multi-tone symbols, and a number (z) of forward-error-correction control symbols in the discrete multitone symbol.
- View Dependent Claims (29, 30, 31, 32)
- - 29. The method of claim 28 wherein the selecting comprises selecting an adjustment value per subchannel based on the signal-to-noise ratio and the number of subchannels associated with the signal-to-noise ratio;
    - and adjusting a number of bits per subchannel for at least one subchannel in accordance with the adjustment value.
  - 30. The method of claim 28 wherein the signal-to-noise ratio is an average signal-to-noise ratio of the associated number of subchannels.
  - 31. The method of claim 28 further comprising:
    - storing, in a table, the number (s) of discrete multi-tone symbols in the forward-error-correction frame, the number (z) of forward-error-correction control symbols in the discrete multitone symbol associated with the signal-to-noise ratio and the number of subchannels associated with the signal-to-noise ratio, for different values of s, z, signal-to-noise ratios and numbers of subchannels.
  - 32. The method of claim 31 wherein for each value of signal-to-noise ratio and number of bits per subchannel of the table, the associated value of s and z provide a maximal net coding gain g_n, and the associated value of s and z is selected from a subset of associated s and z values.

33. An apparatus for determining an uncoded bit error rate p_bbased on a target symbol error rate ε
- _e, comprising;
  
  means for determining the uncoded bit error rate p_bbased on a weighted series expansion of the target symbol error rate ε
  
  _s, comprising weights W that are a function of a maximum number of symbol errors that can be corrected t and a number of symbols in an information field K; and
  
  means for selecting the maximum number of symbol errors t and the number of symbols in the information field K such that the uncoded bit error rate p_bthat produces a symbol error rate that is less than or equal to the target symbol error rate ε
  
  _sis largest.
- View Dependent Claims (34, 35, 36)
- - 34. The apparatus of claim 33 wherein the weighted series expansion comprises at least a first term, wherein second order and higher terms are ignored to determine the uncoded bit error rate p_b.
  - 35. The apparatus of claim 33 wherein the symbols comprise Reed-Solomon symbols.
  - 36. The apparatus of claim 33 wherein the weighted series expansion to determine the uncoded bit error p_brate comprises the following relationship:

37. An apparatus for determining an optimum bit load per subchannel in a multicarrier system with forward error correction, comprising:
- means for computing one or more values of a maximum number of symbol errors that can be corrected t, and a number of symbols in the information field K to determine the optimum bit load per subchannel in accordance with the following relationship;
  
  $1 - {(1 - W (t, K) ɛ_{S}^{\frac{1}{t + 1}})}^{1 / α} = ω (b) (1 - 2^{- b_{i} (t, K) / 2}) erfc (\sqrt{3 \cdot 10^{γ_{i} / 10} / (2^{b_{i} (t, K) + 1} - 2)}) \times [2 - (1 - 2^{- b_{i} (t, K) / 2}) erfc (\sqrt{3 \cdot 10^{γ_{i} / 10} / (2^{b_{i} (t, K) + 1} - 2)})]$ $wherein W (t, K) = {[(\begin{matrix} K + C + R - 1 \\ t \end{matrix})]}^{- \frac{1}{(t + 1)}}, ω (b) = \frac{1}{b \cdot 2^{b}} \sum_{t = 1}^{2^{b}} \sum_{j \neq i}^{χ_{i}} \frac{d_{H} (a_{i}, a_{j})}{χ_{i}},$ ε
  
  _srepresents a target symbol error rate, C+R represents a number of symbols in an error correction field, b represents a number of bit positions of a quadrature-amplitude-modulation symbol, ω
  
  (b) represents an average fraction of erroneous bits in an erroneous b-sized quadrature-amplitude-modulation symbol, a_irepresents a label for the i^thpoint of a constellation associated with a subchannel, a_jrepresents a label for the j^thpoint of a constellation associated with a subchannel, χ
  
  _irepresents a coordination number of the a_l^thpoint, d_H(a_i,a_j) represents a Hamming distance between respective binary vectors associated with points a_iand a_j; and
  
  means for selecting the maximum number of symbol errors that can be corrected t, and the number of symbols in the information field K such that the uncoded bit error rate p_bthat produces a symbol error rate that is less than or equal to the target symbol error rate is increased.

38. An apparatus for determining an optimum bit load per subchannel in a multicarrier system with forward error correction, comprising:
- means for computing one or more values of a maximum number of symbol errors that can be corrected t, and a number of symbols in the information field K to determine the optimum bit load per subchannel in accordance with the following relationship;
  
  $1 - {(1 - W (t, K) ɛ_{S}^{\frac{1}{t + 1}})}^{1 / α} = ω (b) (1 - 2^{- b_{i} (t, K) / 2}) erfc (\sqrt{3 \cdot 10^{γ_{i} / 10} / (2^{b_{i} (t, K) + 1} - 2)}) \times [2 - (1 - 2^{- b_{i} (t, K) / 2}) erfc (\sqrt{3 \cdot 10^{γ_{i} / 10} / (2^{b_{i} (t, K) + 1} - 2)})]$ $wherein W (t, K) = {[(\begin{matrix} K + C + R - 1 \\ t \end{matrix})]}^{- \frac{1}{(t + 1)}},$ ε
  
  _srepresents a target symbol error rate, C+R represents a number of symbols in an error correction field, b represents a number of bit positions of a quadrature-amplitude-modulation symbol, ω
  
  (b) represents an approximate average fraction of erroneous bits in an erroneous b-sized quadrature-amplitude-modulation symbol; and
  
  selecting the maximum number of symbol errors that can be corrected t, and the number of symbols in the information field K such that the uncoded bit error rate p_bthat produces a symbol error rate that is less than or equal to the target symbol error rate is increased.
- View Dependent Claims (39)
- - 39. The apparatus of claim 38 wherein ω
    - (b_i) is determined in accordance with the following relationship;

40. An apparatus for selecting forward error correction parameters in a channel having a plurality of subchannels in a multicarrier communications system, comprising:
- means for determining a signal-to-noise ratio representing a subset of the subchannels; and
  
  means for selecting forward error correction parameters of the channel based on the signal-to-noise ratio.
- View Dependent Claims (41, 42, 43, 44, 45, 46, 47, 48, 49, 50)
- - 41. The apparatus of claim 40 wherein the subset of the subchannels comprises all of the subchannels of the channel.
  - 42. The apparatus of claim 40 wherein the forward error correction parameters are utilized in Reed-Solomon encoding.
  - 43. The apparatus of claim 40 wherein the signal-to-noise ratio is an average signal-to-noise ratio of respective signal-to-noise ratios of the subset of the subchannels.
  - 44. The apparatus of claim 40 further comprising:
    - means for determining a signal-to-noise ratio representing all of the subchannels.
  - 45. The apparatus of claim 40 wherein the means for selecting comprises means for applying a mean field approximation to evaluate a bit load over the subset of subchannels.
  - 46. The apparatus of claim 40 wherein the means for selecting comprises means for adjusting the mean field approximation.
  - 47. The apparatus of claim 46 wherein the means for adjusting is applied when the number of bits per subchannel is less than or equal to two.
  - 48. The apparatus of claim 46 wherein the means for adjusting is a linear adjustment with respect to a bit load of a subchannel.
  - 49. The apparatus of claim 46 further comprising:
    - means for determining the representative performance measurement as an average signal-to-noise ratio γ
      
      _efffor the channel in accordance with the following relationship;
      
      $γ_{eff} = \frac{1}{n_{eff}} \sum_{γ_{i} > γ_{*}} γ_{i}, wherein n_{eff} = \sum_{γ_{i} > γ_{*}} 1,$ γ
      
      _irepresents a signal-to-noise ratio measurement for an ith subchannel, and n_effrepresents a number of subchannels for which the signal-to-noise ratio γ
      
      _iwas measured for which γ
      
      _lis greater than γ
      
      *, and γ
      
      * represents a threshold signal-to-noise ratio.
  - 50. The apparatus of claim 49 further comprising:
    - means for determining the representative performance measurement as an average signal-to-noise ratio γ
      
      _efffor the channel in accordance with the following relationship;
      
      $γ_{eff} = \frac{1}{n_{eff}} \sum_{γ_{i} > γ_{*}} γ_{i}, wherein n_{eff} = \sum_{γ_{i} \geq γ_{*}} 1,$ γ
      
      _irepresents a signal-to-noise measurement for an ith subchannel, and n_effrepresents a number of subchannels for which the signal-to-noise ratio γ
      
      _lwas measured for which γ
      
      _lis greater than or equal to than γ
      
      *, and γ
      
      * represents a threshold signal-to-noise ratio.

51. An apparatus for determining a bit load b per subchannel in a multicarrier system with forward error correction, comprising:
- means for computing one or more values of a maximum number of symbol errors that can be corrected t, and a number of symbols in the information field K to determine the bit load per subchannel in accordance with the following relationship;
  
  b=[γ
  
  +Φ
  
  (γ
  
  ,t,K,ε
  
  )]/10 log 2 , wherein $Φ (γ, t, K, ɛ) = 10 \log {10^{- γ / 10} + \frac{3 \log e}{\begin{matrix} 2 \log [\frac{α 〈 ω (b) 〉 \sqrt{8 / π}}{W (t, K) {(αɛ / β)}^{\frac{1}{(t + 1)}}}] - \\ \log \log [\frac{α 〈 ω (b) 〉 \sqrt{8 / π}}{W (t, K) {(αɛ / β)}^{\frac{1}{(t + 1)}}}] + \log (\frac{\log e}{2}) \end{matrix}}}, W (t, K) = {{[(\begin{matrix} K + C + R - 1 \\ t \end{matrix})]}^{- \frac{1}{(t + 1)}} [(\begin{matrix} K + C + R \\ t + 1 \end{matrix})]}^{- \frac{k - 1}{(t + 1)}}, 〈 ω (b) 〉 = \frac{1}{b_{\max}} \int_{1}^{b_{\max}} ω (b) (1 - 2^{- b / 2}) \partial b$ α
  
  represents a number of bits per symbol, γ
  
  represents a signal-to-noise ratio, t represents a maximum number of symbol errors that can be corrected, ε
  
  represents a target bit error rate, C+R represents a number of symbols in an error correction field, b represents a number of bit positions of a quadrature-amplitude-modulation symbol, ω
  
  (b) represents an average fraction of erroneous bits in an erroneous b-sized quadrature-amplitude-modulation symbol, b_max, is a maximum bit load per subchannel; and
  
  means for selecting a bit load per subchannel in accordance with the maximum number of symbol errors that can be corrected t, and a number of symbols in the information field K.
- View Dependent Claims (52, 53)
- - 52. The apparatus of claim 51 wherein Φ
    - (γ
      
      ,t,K,ε
      
      ) is evaluated at γ
      
      equals −
      
      ∞
      
      .
  - 53. The apparatus of claim 51 wherein b is greater than or equal to three.

54. An apparatus for selecting forward error correction parameters for use in a channel having a plurality of subchannels, comprising:
- means for determining an average signal-to-noise ratio of at least a subset of the subchannels; and
  
  means for selecting forward error correction parameters based on the average signal-to-noise ratio, and a count of the number of subchannels in the subset.
- View Dependent Claims (55, 56)
- - 55. The apparatus of claim 54 wherein the means for selecting the forward error correction parameters selects the forward error correction parameters based on a predicted gain from application of the selected forward error correction parameters.
  - 56. The apparatus of claim 55 wherein the gain is a performance gain.

57. An apparatus for selecting at least one forward error correction parameter, comprising:
- means for computing one or more values representing a number of information symbols K in a frame accordance with the following relationship;
  
  $[\frac{α (K + s + zs)}{s n_{eff}} + 1.5] [1 - {(1 - ({[(\begin{matrix} K + C + R - 1 \\ t \end{matrix})]}^{- \frac{1}{(t + 1)}}) ɛ_{S}^{1 / (t + 1)})}^{1 / α}] = 2 (1 - 2^{\frac{α (K + s + zs)}{2 {sn}_{eff}}}) erfc (\sqrt{1.5 \cdot 10^{γ_{eff} / 10} / (2^{\frac{α (K + s + zs)}{{sn}_{eff}}} - 1)}) \times [2 - (1 - 2^{\frac{α (K + s + zs)}{2 {sn}_{eff}}}) erfc (\sqrt{1.5 \cdot 10^{γ_{eff} / 10} / (2^{\frac{α (K + s + zs)}{{sn}_{eff}}} - 1)})] wherein t = ⌊ \frac{sz + 1 + e_{r}}{2} ⌋, e_{r} \leq sz, and$ s represents a number of discrete multi-tone symbols in a frame, z represents a number of error correction symbols in a discrete multi-tone symbol, α
  
  represents a number of bits per code symbol, C+R represents a number of redundant symbols in an error correction field, n_effrepresents a number of subchannels exceeding a threshold performance value, γ
  
  _effrepresents an effective signal-to-noise ratio associated with the number of subchannels exceeding the threshold performance value, ε
  
  _srepresents a target symbol error rate; and
  
  e_rrepresents a number of erasures; and
  
  means for determining a number of bits per subchannel in accordance with the one or more values of K.
- View Dependent Claims (58, 59, 60)
- - 58. The apparatus of claim 57 wherein K is a continuous variable.
  - 59. The apparatus of claim 57 wherein K is computed using dichotomy, for values of γ
    - _eff, n_eff, z, and s.
  - 60. The apparatus of claim 57 further comprising:
    - means for determining a net coding gain associated with values of γ
      
      _eff, n_eff, z, and s;
      
      means for determining an incremental number of bits per subchannel associated with the net coding gain; and
      
      means for storing associated values of γ
      
      _eff, n_eff, z, s and the incremental number of bits per subchannel.

61. An apparatus for selecting transmission parameters of a multicarrier system having a channel comprising a plurality of subchannels, comprising:
- means for selecting a number (s) of discrete multi-tone symbols in a forward-error-correction frame, and a number (z) of forward-error-correction control symbols in a discrete multitone symbol based on a signal-to-noise ratio and a number of subchannels associated with the signal-to-noise ratio; and
  
  means for transmitting information in accordance with the selected number (s) of discrete multi-tone symbols, and a number (z) of forward-error-correction control symbols in the discrete multitone symbol.
- View Dependent Claims (62, 63, 64, 65)
- - 62. The apparatus of claim 61 wherein the means for selecting comprises:
    - selecting an adjustment value per subchannel based on the signal-to-noise ratio and the number of subchannels associated with the signal-to-noise ratio; and
      
      means for adjusting a number of bits per subchannel for at least one subchannel in accordance with the adjustment value.
  - 63. The apparatus of claim 61 wherein the signal-to-noise ratio is an average signal-to-noise ratio of the associated number of subchannels.
  - 64. The apparatus of claim 61 further comprising:
    - means for storing, in a table, the number (s) of discrete multi-tone symbols in the forward-error-correction frame, the number (z) of forward-error-correction control symbols in the discrete multitone symbol associated with the signal-to-noise ratio and the number of subchannels associated with the signal-to-noise ratio, for different values of s, z, signal-to-noise ratios and numbers of subchannels.
  - 65. The apparatus of claim 64 wherein for each value of signal-to-noise ratio and number of bits per subchannel of the table, the associated value of s and z provides a maximal net coding gain, and the associated value of s and z is selected from a subset of associated s and z values.

Specification

Resources

Litigation Campaign Assessment

Current Assignee
Hewlett-Packard Development Company, L.P. (HP Inc.)
Original Assignee
3Com Corporation (HP Inc.)
Inventors
Mitlin, Vlad, Williams, Richard G.C.

Granted Patent

US 7,131,038 B2
Time in Patent Office

Days
Field of Search
US Class Current

714/708
CPC Class Codes

H04L 1/0009   by adapting the channel cod...

H04L 1/1825   Adaptation of specific ARQ ...

H04L 5/0044   allocation of payload

Performance evaluation of multicarrier channels

First Claim

5 Assignments

0 Petitions

Accused Products

Abstract

67 Citations

65 Claims

Specification

Solutions

Use Cases

Quick Links

Performance evaluation of multicarrier channels

First Claim

5 Assignments

Subscription Required

Subscription Required

0 Petitions

Subscription Required

Accused Products

Subscription Required

Abstract

67 Citations

65 Claims

Specification

Subscription Required

Solutions

Use Cases

Quick Links