Radio communication using OFDMA and IFDMA
View Patent ↗In a method for communicating by radio, a frequency band divided up into a plurality of subcarriers is used for the communication. Messages are sent from a base station to a user station and/or from the user station to the base station. Messages are processed at some times using a first FDMA method such as for example OFDMA and at other times using a second FDMA method such as for example IFDMA. A transmitter and a receiver implement the method.
1. A method of communicating by radio, comprising:
sending messages using a frequency band (F) divided into a plurality of subcarriers, either from a base station (BS) to a user station or from the user station to the base station (BS); and
processing the received messages using either a first or a second Frequency Division Multiple Access (FDMA) method, wherein
the plurality of subcarriers are divided into first, second and third discrete groups,
first and second adjacent base stations are in communication with the user station, the first base station using the first, second and third discrete groups of subcarriers, the second base station using the first and third discrete groups of subcarriers, and
a different frequency repetition spacing is employed for those subcarriers which are used for communication by the user station at an edge of a radio cell than for the subcarriers which are used for communication by the user station in a remainder of the cell.
2. A method according to claim 1 , wherein the base station (BS) sends to the user station signaling information as a request to change from the first FDMA method to the second FDMA method or from the second FDMA method to the first FDMA method.
3. A method according to claim 1 , wherein the first or the second FDMA method is used depending on at least one measurement result.
4. A method according to claim 3 , wherein the at least one measurement result is at least one of a radio channel quality relating to at least one subcarrier, a peak-to-average ratio of the user station, an interference situation of the user station, and an actual location of the user station.
5. A method according to claim 1 , wherein, when the first FDMA method is used, a first group of subcarriers is used, and when the second FDMA method is used, a second group of subcarriers different than the first group is used, and
wherein the first group is a plurality of blocks of the subcarriers which are equidistant in the frequency band, and each block has an equal number of subcarriers.
6. A method according to claim 1 , wherein,
when the first FDMA method is used, the first group of subcarriers is used, and when the second FDMA method is used, the second group of subcarriers different from the first group is used, and
wherein the second base station (BS) adjacent to the first base station (BS) uses at least some of the subcarriers of the first group when the first FDMA method is used and at least some of the third group of subcarriers when the second FDMA method is used to communicate with the base station.
7. A transmitter for a radio communication system, comprising:
a processor processing the first messages to be sent when using a first Frequency Division Multiple Access (FDMA) method and processing second messages to be sent when using a second FDMA method; and
a sending unit sending the processed messages to a receiver via a frequency band (F) subdivided into a plurality of subcarriers, wherein
the plurality of subcarriers are divided into first, second and third discrete groups,
first and second adjacent base stations are in communication with the user station, the first base station using the first, second and third discrete groups of subcarriers, the second base station using the first and third discrete groups of subcarriers, and
a different frequency repetition spacing is employed for those subcarriers which are used for communication by the user station at an edge of a radio cell than for the subcarriers which are used for communication by the user station in a remainder of the cell.
8. A receiver for a radio communication system, comprising:
a receiving unit receiving messages from a transmitter via a frequency band (F) subdivided into a plurality of subcarriers, the messages including first messages processed using a first Frequency Division Multiple Access (FDMA) method and/or second messages processed using a second FDMA method; and
a processor processing first messages received using a first FDMA method and processing second messages when using a second FDMA method, wherein
the plurality of subcarriers are divided into first, second and third discrete groups,
first and second adjacent base stations are in communication with the user station, the first base station using the first, second and third discrete groups of subcarriers, the second base station using the first and third discrete groups of subcarriers, and
a different frequency repetition spacing is employed for those subcarriers which are used for communication by the user station at an edge of a radio cell than for the subcarriers which are used for communication by the user station in a remainder of the cell.