Data communication apparatus and method based on orthogonal frequency division multiple access
First Claim
1. A data communication apparatus based on orthogonal frequency division multiple access (OFDMA) comprising a first user transmitting unit through which a user transmits user information to a base station in units of first symbol blocks each including a first predetermined number M of symbols in data communication between the user and the base station, the first user transmitting unit comprising:
- a first encoder for generating a first sub-block composed of a second predetermined number Mu of user symbols ak(u) for a u-th user by encoding the user information, where Mu is an integer greater than or equal to 1 and no greater than M, “
k”
is a time index and an integer greater than or equal to 0 and no greater than M−
1, “
u”
is a user index and an integer greater than or equal to 1 and no greater than U, and U indicates the number of users sharing the first symbol block and is 1 or a positive integer greater than 1;
a first block repeater for repeating the first sub-block a third predetermined number Lu of times to generate M symbols ak′
(u), wherein Lu is M/Mu, k′
=k % Mu, and k % Mu indicates the remainder when “
k”
is divided by Mu;
a first multiplier for multiplying the M symbols ak′
(u) generated from the first block repeater by γ
u exp(j2π
kmu/M) and outputting the result of multiplication as a signal xk(u) for the u-th user, wherein γ
u indicates a magnitude control factor for the u-th user signal xk(u), and mu indicates a unique frequency offset number allocated to the u-th user;
a first cyclic extension symbol inserter for outputting the first symbol block completed by inserting a cyclic extension symbol into the u-th user signal xk(u); and
a first signal transmitter for converting the completed first symbol block into a symbol block signal and transmitting the symbol block signal, wherein M1+M2+M3+ . . . +Mu does not exceed M.
1 Assignment
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Accused Products
Abstract
A data communication apparatus and method based on OFDMA are provided. In a first user transmitting unit through which a user transmits user information to a base station in units of first symbol blocks each including M symbols, a first encoder generates a first sub-block composed of Mu user symbols for a u-th user by encoding the user information. A first block repeater repeats the first sub-block Lu times to generate M symbols. A first multiplier multiplies the M symbols by γu exp(j2πkmu/M) and outputs a u-th user signal. A first cyclic extension symbol inserter inserts a cyclic extension symbol into the u-th user signal and generates a single complete first symbol block. Accordingly, data transmission speed can be freely changed, a very small PAR can be provided, influence of the signal interference is greatly reduced, interference occurring between received blocks due to channels can be prevented, and distortion between channels can be effectively compensated for.
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Citations
77 Claims
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1. A data communication apparatus based on orthogonal frequency division multiple access (OFDMA) comprising a first user transmitting unit through which a user transmits user information to a base station in units of first symbol blocks each including a first predetermined number M of symbols in data communication between the user and the base station, the first user transmitting unit comprising:
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a first encoder for generating a first sub-block composed of a second predetermined number Mu of user symbols ak(u) for a u-th user by encoding the user information, where Mu is an integer greater than or equal to 1 and no greater than M, “
k”
is a time index and an integer greater than or equal to 0 and no greater than M−
1, “
u”
is a user index and an integer greater than or equal to 1 and no greater than U, and U indicates the number of users sharing the first symbol block and is 1 or a positive integer greater than 1;
a first block repeater for repeating the first sub-block a third predetermined number Lu of times to generate M symbols ak′
(u), wherein Lu is M/Mu, k′
=k % Mu, and k % Mu indicates the remainder when “
k”
is divided by Mu;
a first multiplier for multiplying the M symbols ak′
(u) generated from the first block repeater by γ
u exp(j2π
kmu/M) and outputting the result of multiplication as a signal xk(u) for the u-th user, wherein γ
u indicates a magnitude control factor for the u-th user signal xk(u), and mu indicates a unique frequency offset number allocated to the u-th user;
a first cyclic extension symbol inserter for outputting the first symbol block completed by inserting a cyclic extension symbol into the u-th user signal xk(u); and
a first signal transmitter for converting the completed first symbol block into a symbol block signal and transmitting the symbol block signal, wherein M1+M2+M3+ . . . +Mu does not exceed M. - View Dependent Claims (3, 4, 39, 41, 42, 43)
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2. A data communication apparatus based on orthogonal frequency division multiple access (OFDMA) in data communication between a fourth predetermined number V of users and a base station, V indicating the number of users sharing a second symbol block and being 1 or a positive integer greater than 1, the data communication apparatus comprising a first base station transmitting unit through which the base station transmits base station information to a v-th user in units of the second symbol blocks each including a fifth predetermined number N of symbols “
- v”
being a user index and an integer greater than or equal to 1 and no greater than V, the first base station transmitting unit comprising;
second through (V+1)-th encoders;
second through (V+1)-th block repeaters;
second through (V+1)-th multipliers;
a first adder;
a second cyclic extension symbol inserter; and
a second signal transmitter, wherein the (v+1)-th encoder generates a (v+1)-th sub-block composed of a sixth predetermined number Nv of base station symbols ak(v) for a v-th user by encoding the base station information and outputs the (v+1)-th sub-block to the (v+1)-th block repeater, Nv being an integer greater than or equal to 1 and less than or equal to N, “
k”
being a time index and an integer greater than or equal to 0 and less than or equal to N−
1,the (v+1)-th block repeater repeats the (v+1)-th sub-block a seventh predetermined number Lv of times to generate N symbols ak′
(v) and outputs the N symbols ak′
(v) to the (v+1)-th multiplier, Lv being N/Nv, k′
=k % Nv, k % Nv indicating the remainder when “
k”
is divided by Nv,the (v+1)-th multiplier multiplies the N symbols ak′
(v) by γ
v exp(j2π
knv/N) and outputs the result xk(v) of multiplication to the first adder, γ
v indicating a magnitude control factor for a v-th user signal, nv indicating a unique frequency offset number allocated to the v-th user,the first adder sums the results xk(1) through xk(V) of multiplication received from the second through (V+1)-th multipliers and outputs the result xk of summation to the second cyclic extension symbol inserter, the second cyclic extension symbol inserter outputs the single second symbol block completed by inserting a cyclic extension symbol into the result xk of summation to the second signal transmitter, the second signal transmitter converts the completed second symbol block into a symbol block signal and transmits the symbol block signal, and N1+N2+N3+ . . . +Nv does not exceed N. - View Dependent Claims (40)
- v”
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5. A data communication apparatus based on orthogonal frequency division multiple access (OFDMA) comprising a first base station receiving unit which receives a symbol block signal transmitted from each of U first user transmitting units and estimates u-th user symbols from the symbol block signal, U indicating the number of users sharing a first symbol block having M symbols and being 1 or a positive integer greater than 1, “
- u”
being a user factor and an integer greater than or equal to 1 and no greater than M, the first base station receiving unit comprising;
a first signal receiver for converting the received symbol block signal into the first symbol block and outputting the first symbol block;
a first pre-processor for finding a start point of the first symbol block received from the first signal receiver, removing a cyclic extension symbol from the first symbol block on the basis of the start point, and outputting the result rk of removal of the cyclic extension symbol, wherein “
k”
is a time index and an integer greater than or equal to 0 and less than or equal to M−
1;
a first user symbol extractor for extracting only the u-th user symbols from the result rk received from the first pre-processor; and
a first estimate value detector for detecting an estimate value â
k(u) for a u-th user symbol from the u-th user symbols extracted by the first user symbol extractor. - View Dependent Claims (6, 7, 8, 9, 10, 11, 18, 20, 21, 22, 49, 50, 51, 52, 53, 54, 61, 62, 63, 64)
- u”
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12. A data communication apparatus based on orthogonal frequency division multiple access (OFDMA) comprising a first user receiving unit which receives a symbol block signal transmitted from a first base station transmitting units and estimates a base station symbol for a v-th user from the received symbol block signal, “
- v”
being a user factor and an integer greater than or equal to 1 and no greater than V, V indicating the number of users sharing a second symbol block having N symbols and being 1 or a positive integer greater than 1, the first user receiving unit comprising;
a second signal receiver for converting the symbol block signal received from the first base station transmitting unit into the second symbol block and outputting the second symbol block;
a second pre-processor for finding a start point of the second symbol block received from the second signal receiver, removing a cyclic extension symbol from the second symbol block on the basis of the start point, and outputting the result rk of removal of the cyclic extension symbol, wherein k″
is a time index and an integer greater than or equal to 0 and less than or equal to N−
1;
a first base station symbol extractor for extracting only symbols for the v-th user from the result rk received from the second pre-processor; and
a second estimate value detector for detecting an estimate value â
k(v) of the base station symbol for the v-th user from the symbols for the v-th user output from the first base station symbol extractor. - View Dependent Claims (13, 14, 15, 16, 17, 19, 55, 56, 57, 58, 59, 60)
- v”
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23. A data communication apparatus based on orthogonal frequency division multiple access (OFDMA) comprising a second user transmitting unit through which a user transmits user information to a base station in units of two first symbol blocks each including a first predetermined number M of symbols in data communication between the user and the base station, the second user transmitting unit comprising:
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a first encoder for generating a first sub-block composed of a second predetermined number Mu of user symbols ak(u) for a u-th user by encoding the user information, where Mu is an integer greater than or equal to 1 and no greater than M, “
k”
is a time index and an integer greater than or equal to 0 and no greater than M-1, “
u”
is a user index and an integer greater than or equal to 1 and no greater than U, and U indicates the number of users sharing the first symbol block and is 1 or a positive integer greater than 1;
first and second block transmitters; and
a first diversity signal generator for transforming odd- and even-numbered first sub-blocks received from the first encoder every symbol block time and alternately outputting untransformed and transformed odd- and even-numbered first sub-blocks to each of the first and second block transmitters every symbol block time, wherein each of the first and second block transmitters comprises a first block repeater, a first multiplier, a first cyclic extension symbol inserter, and a first signal transmitter and generates two symbol block signals from the untransformed and transformed odd- and even-numbered first sub-blocks alternately output from the first diversity signal generator, the first block repeater repeats the first sub-block a third predetermined number Lu of times to generate M symbols ak′
(u), wherein Lu is M/Mu, k′
=k % Mu, and k % Mu indicates the remainder when “
k”
is divided by Mu,the first multiplier multiplies the M symbols ak′
(u) generated from the first block repeater by γ
u exp(j2π
kmu/M) and outputs the result of multiplication as a signal xk(u) for the u-th user, wherein γ
u indicates a magnitude control factor for the u-th user signal xk(u), and mu indicates a unique frequency offset number allocated to the u-th user,the first cyclic extension symbol inserter outputs the first symbol block completed by inserting a cyclic extension symbol into the u-th user signal xk(u), the first signal transmitter converts the completed first symbol block into a symbol block signal and transmits the symbol block signal, and M1+M2+M3+ . . . +MU does not exceed M. - View Dependent Claims (24, 27, 28, 29, 65, 67, 68)
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25. A data communication apparatus based on orthogonal frequency division multiple access (OFDMA) in data communication between a fourth predetermined number V of users and a base station, V indicating the number of users sharing a second symbol block and being 1 or a positive integer greater than 1, the data communication apparatus comprising a second base station transmitting unit through which the base station transmits base station information to a v-th user in units of two second symbol blocks each including a fifth predetermined number N of symbols, the second base station transmitting unit comprising:
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second through (V+1)-th encoders;
third and fourth block transmitters; and
second through (V+1)-th diversity signal generators, wherein the (v+1)-th encoder generates a (v+1)-th sub-block composed of a sixth predetermined number Nv of base station symbols ak(v) for a v-th user by encoding the base station information and outputs the (v+1)-th sub-block to the (v+1)-th block repeater, Nv being an integer greater than or equal to 1 and less than or equal to N, “
k”
being a time index and an integer greater than or equal to 0 and less than or equal to N-1,the (v+1)-th diversity signal generator transforms odd- and even-numbered (v+1)-th sub-blocks received from the (v+1)-th encoder every symbol block time and outputs alternately untransformed and transformed odd- and even-numbered (v+1)-th sub-blocks to the third and fourth block transmitters every symbol block time, and each of the third and fourth block transmitters comprises second through (V+1)-th block repeaters, second through (V+1)-th multipliers, a first adder, a second cyclic extension symbol inserter, and a second signal transmitter, and generates two symbol block signals from the untransformed and transformed odd- and even-numbered second through (V+1)-th sub-blocks alternately output from each of the second through (V+1)-th diversity signal generators, the (v+1)-th block repeater repeats the (v+1)-th sub-block a seventh predetermined number Lv of times to generate N symbols ak′
(v) and outputs the N symbols ak′
(v) to the (v+1)-th multiplier, Lv being N/Nv, k′
=k % Nv, k % Nv indicating the remainder when “
k”
is divided by Nv,the (v+1)-th multiplier multiplies the N symbols ak′
(v) by γ
v exp(j2π
knv/N) and outputs the result xk(v) of multiplication to the first adder, γ
v indicating a magnitude control factor for a v-th user signal, nv indicating a unique frequency offset number allocated to the v-th user,the first adder sums the results xk(1) through xk(V) of multiplication received from the second through (V+1)-th multipliers and outputs the result xk of summation to the second cyclic extension symbol inserter, the second cyclic extension symbol inserter outputs the single second symbol block completed by inserting a cyclic extension symbol into the result xk of summation to the second signal transmitter, the second signal transmitter converts the completed second symbol block into a symbol block signal and transmits the symbol block signal, and N1+N2+N3+ . . . +Nv does not exceed N. - View Dependent Claims (26, 32, 33, 34, 35, 36, 37, 38, 66, 72, 73, 75, 76, 77)
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30. The data communication apparatus of 28, wherein the first diversity equalizer calculates Z1,n and Z2,n according to:
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31. The data communication apparatus of 28, wherein the first diversity equalizer calculates Z1,n and Z2,n according to:
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44. A data communication method based on orthogonal frequency division multiple access (OFDMA) through which a data communication apparatus based on OFDMA generates a channel estimation pilot symbol including at least 2M (2N) symbols, the data communication method comprising:
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(k1) setting a reference pilot symbol sequence d[k] composed of M (N) pilot symbols previously known to a user and a base station, “
k”
being an integer greater than or equal to 0 and no greater than M−
1 (N−
1), “
[ ]”
indicating a set; and
(l1) obtaining the pilot symbol d(u)[e] (d(v)[e]) for a u-th (v-th) user according to d(u)[e]=d[mu+e·
Lu] (d(v)[e]=d[nv+e·
Lv]), where “
u”
(“
v”
) is a user index and an integer greater than or equal to 1 and no greater than U (V), U (V) indicates the number of users sharing a symbol block having M (N) symbols and is 1 or a positive integer greater than 1, “
e”
is an integer equal to or greater than 0 and no greater than Mu−
1 (Nv−
1), Mu (Nv) is an integer equal to or greater than 1 and no greater than M (N), mu (nv) indicates a unique frequency offset number of the u-th (v-th) user, Lu (Lv) is M/Mu (N/Nv). - View Dependent Claims (46, 47, 48)
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45. A data communication method based on orthogonal frequency division multiple access (OFDMA) through which a data communication apparatus based on OFDMA generates a channel estimation pilot symbol including at least 2M (2N) symbols, the data communication method comprising:
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(k2) setting a reference pilot symbol sequence d[k] composed of M (2N) pilot symbols previously known to a user and a base station, “
k”
being an integer greater than or equal to 0 and no greater than M−
1 (N−
1), “
[ ]“
indicating a set; and
(12) obtaining the pilot symbol d(u)[e] (d(v)[e]) for a u-th (v-th) user according to d(u)[e]=d[e+Su−
1](d(v)[e]=d[e+Sv−
1]), where “
u”
(“
v”
) is a user index and an integer greater than or equal to 1 and less than or equal to U (V), U (V) indicates the number of users sharing a symbol block having M (2N) symbols and is 1 or a positive integer greater than 1, “
e”
is an integer equal to or greater than 0 and less than or equal to Mu−
1 (Nv−
1), Mu (Nv) is an integer equal to or greater than 1 and less than or equal to M (N), mu (nv) indicates a unique frequency offset number of the u-th (v-th) user, Lu (Lv) is M/Mu (N/Nv),and S0=0.
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69. The data communication method of 68, wherein the step (p3) comprises detecting the estimate value â
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1,k(u) of the odd-numbered user symbol from the result z1,k(u) of inverse Fourier transform performed in step (o34), and detecting the estimate value â
2,k(u) of the even-numbered user symbol from the result z2,k(u) of inverse Fourier transform performed in step (o34).
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1,k(u) of the odd-numbered user symbol from the result z1,k(u) of inverse Fourier transform performed in step (o34), and detecting the estimate value â
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70. The data communication method of 68, wherein the step (o33) comprises calculating Z1,n and Z2,n according to:
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71. The data communication method of 68, wherein the step (o33) comprises calculating Z1,n and Z2,n according to:
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74. The data communication method of 73, wherein the step (p4) comprises detecting the estimate value â
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1,k(v) of the odd-numbered base station symbol for the v-th user from the result z1,k(v) of inverse Fourier transform performed in step (o44), and detecting the estimate value â
2,k(v) of the odd-numbered base station symbol for the v-th user from the result z2,k(v) of inverse Fourier transform performed in step (o44).
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1,k(v) of the odd-numbered base station symbol for the v-th user from the result z1,k(v) of inverse Fourier transform performed in step (o44), and detecting the estimate value â
Specification