US 7,072,419 B2 · Data communication apparatus and method based on orthogonal frequency division multiple access

Abstract

A data communication apparatus and method based on orthogonal frequency division multiple access (OFDMA) are provided. In the data communication apparatus, a (U+1)-th encoder in a u-th user transmitting unit among U user transmitting units which transmit corresponding user information to a base station part encodes the user information and outputting the result of encoding as Nu u-th user symbols. A user signal generator generates a u-th user signal xk(u) in a temporal domain from the u-th user symbol Am(u) received from the (U+1)-th encoder according to a formula, xk(u)=ak % Nu(u) exp(j2πknu/N). A second cyclic extension symbol inserter inserts a cyclic extension symbol into the u-th user signal. A second signal transmitter converts the result of insertion into a symbol block signal and transmitting the symbol block signal to the base station part. Here, 1≦NU<N. Accordingly, the hardware of a user part can be optionally simplified very much. Communication efficiency can be increased in a given channel environment. In addition, different types of user parties having different complexities can communicate with a base station part using a single data format.

Claims15

Dependent claims

A data communication apparatus based on orthogonal frequency division multiple access (OFDMA) comprising a base station transmitting unit which transmits user information for at least one user, the base station transmitting unit comprising:

first through U-th encoders among which a u-th encoder (where 1≦u≦U, and U indicates the number of users) encodes the user information and outputs the result of encoding as Nu u-th user symbols (where Nu is the number of symbols allocated to a u-th user);
a frequency allocator for allocating different frequencies to the user symbols received from each of the first through U-th encoders and outputting the results of allocation;
a first inverse Fourier transformer for performing N-point inverse Fourier transform on the results of allocation received from the frequency allocator (where N is a total number of symbols which can be allocated to the U users);
a first cyclic extension symbol inserter for inserting a cyclic extension symbol into the result of inverse Fourier transform;
and
a first signal transmitter for converting the result of insertion into a symbol block signal and transmitting the symbol block signal to the user,
wherein the sum of N1 through NU is no greater than N.

4 more elements

A data communication apparatus based on orthogonal frequency division multiple access (OFDMA) comprising U user transmitting units each of which transmits user information to a base station part, a u-th user transmitting unit (1≦u≦U) among the U user transmitting units comprising:

a (U+1)-th encoder for encoding the user information and outputting the result of encoding as Nu u-th user symbols (where Nu is the number of symbols allocated to a u-th user);
a user signal generator for generating a u-th user signal xk(u) in a time domain from the u-th user symbol Am(u) (where 0≦m<Nu) received from the (U+1)-th encoder according to the following formula and outputting the generated u-th user signal xk(u),
xk(u)=ak % Nu(u) exp(j2πknu/N)
where 0≦k≦N−1, N is a total number of symbols which can be allocated to the U users and is at least the sum of N1 through NU, k % Nu indicates the remainder when “k” is divided by Nu, ak(u) indicates the result of performing inverse Fourier transform on the Nu user symbols Am(u), and nu indicates a frequency offset number allocated to a u-th user;
a first cyclic extension symbol inserter for inserting a cyclic extension symbol into the u-th user signal;
and
a first signal transmitter for converting the result of insertion into a symbol block signal and transmitting the symbol block signal to the base station part,
wherein 1≦NU≦N.

5 more elements

Dependencies are inferred from the claim text.

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

Life of this patent

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

Life of this patent

Abstract

Claims15