Data communication apparatus and method based on orthogonal frequency division multiple access

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 γv exp(j2πknv/N) and outputs the result xk(v) of multiplication to the first adder, γv 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 where N represents the number of second symbol blocks in data communication between the user and the base station, Nv is an integer greater than or eciual to 1 and less than or equal to N, ‘v’ is a user index and an integer greater than or equal to 1 and no greater than V, and V indicates the number of users sharing the second symbol block and is 1 or a positive integer greater than 1.

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 âk(u) for a u-th user symbol from the u-th user symbols extracted by the first user symbol extractor.

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 âk(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.

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:

• 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 γu exp(j2πkmu/M) and outputs the result of multiplication as a signal xk(u) for the u-th user, wherein γu 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 where M represents the number of symbols in data communication between the user and the base station, Mu is an integer greater than or equal to 1 and no greater than M, ‘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 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:

• 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 γv exp(j2πknv/N) and outputs the result xk(v) of multiplication to the first adder, γv 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 where N represents the number of second symbol blocks in data communication between the user and the base station, Nv is an integer greater than or equal to 1 and less than or equal to N, ‘v’ is a user index and an integer greater than or equal to 1 and no greater than V, and V indicates the number of users sharing the second symbol block and is 1 or a positive integer greater than 1.

A data communication method based on orthogonal frequency division multiple access (OFDMA) through which a user transmits user information to a base station in units of first symbol blocks each including a first predetermined number of symbols in data communication between the user and a base station, the data communication method comprising:

• (a1) generating a first sub-block composed of a second predetermined number Mu of a user symbols ak(u) for the u-th user by encoding the user information;
• (b1) repeating the first sub-block a third predetermined number Lu of times to generate the M symbols ak′(u);
• (c1) multiplying the M symbols ak′(u) by γu exp(j2πkmu/M) to obtain the u-th user signal xk(u);
• (d1) inserting the cyclic extension symbol into the u-th user signal xk(u) to generate the single complete first symbol block;
• and
• (e1) converting the first symbol block into the symbol block signal and transmitting the symbol block signal.

A data communication method based on orthogonal frequency division multiple access (OFDMA) in a data communication apparatus between a 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 including a first base station transmitting unit through which the first base station transmits base station information to a v-th user in units of symbol blocks each including a 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 data communication method comprising:

• (a2) generating V (v+1)-th sub-blocks each composed of a second predetermined number Nv of base station symbols ak(v) for the v-th user by encoding the base station information;
• (b2) repeating each of the V (v+1)-th sub-blocks Lv times to generate N symbols ak′(v);
• (c2) multiplying the symbols ak′(1) through ak′(V), which are obtained with respect to the respective V (v+1)-th sub-blocks in step (b2), by γ1 exp(j2πkn1/N) through γv exp(j2πknv/N), respectively, to generate xk(1) through xk(V);
• (d2) summing xk(1) through xk(V) and obtaining the result xk of summation;
• (e2) inserting a cyclic extension symbol into the result xk of summation to generate a single complete symbol block;
• and
• (f2) converting the symbol block into a symbol block signal and transmitting the symbol block signal.

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:

• (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
• (l2) 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),
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