Method for using flexible bandwidth in OFDMA-based cognitive radio system, base station and subscriber station using the same

A CPE (customer premises equipment) of an OFDMA (orthogonal frequency division multiple access)-based cognitive radio system comprising:

• a receiver receiving an OFDMA-based signal comprising a preamble sequence that comprises band allocation information indicating information regarding a channel band allocated from a BS (base station) to a secondary user;
• and
• a band allocation information detector detecting the band allocation information based on the received OFDMA-based signal,
• wherein the band allocation information indicating information regarding the allocated channel band,
• wherein the allocated channel band is a channel band of unused channel bands having a bandwidth that is a natural number times a bandwidth resolution, the unused channel bands being channel bands among a range of frequencies allowed to but not used by a primary user,
• wherein the allocated channel band comprises:
• a fraction of a broadcast channel band as the channel band for the CPE according to fractional bandwidth mode information, or
• bonding together a bundle of broadcast channel bands as the channel band for the CPE according to the channel bonding information, or
• a plurality of fractions of a broadcast channel bands as the channel band for the CPE according to the channel bonding information,
• wherein the bandwidth resolution is a predetermined bandwidth smaller than a bandwidth of a broadcast channel band, wherein the allocated channel band is one of a fraction of the broadcast channel band, and a channel band formed by bonding broadcast channel bands or a plurality of fractions of a broadcast channel band.

A method of using a flexible bandwidth through a BS (base station) in an OFDMA (orthogonal frequency division multiple access)-based cognitive radio system, comprising:

• allocating a channel band of unused channel bands having a bandwidth that is a natural number times a bandwidth resolution to a CPE (customer premises equipment) of a secondary user, the unused channel bands being channel bands among a range of frequencies allowed to but not used by a primary user, wherein the bandwidth resolution is a predetermined bandwidth smaller than a bandwidth of a broadcast channel band, wherein the allocated channel band comprises:
• a fraction of a broadcast channel band as the channel band for the CPE according to fractional bandwidth mode information, or
• a bundle of broadcast channel bands bonded together as the channel band for the CPE according to the channel bonding information, or
• a plurality of fractions of a broadcast channel bands as the channel band for the CPE according to the channel bonding information;
• and
• transmitting an OFDMA-based signal comprising a preamble sequence that comprises band allocation information indicating information regarding the allocated channel band, wherein a fraction of the broadcast channel band is allocated as a channel band for the CPE according to fractional bandwidth mode information, or is allocated as a channel band formed by bonding a bundle of broadcast channel bands, or is allocated as a plurality of fractions of a broadcast channel bands allocated as a channel band for the CPE according to the channel bonding information.

A method of using a flexible bandwidth in CPE (customer premises equipment) in an OFDMA (orthogonal frequency division multiple access)-based cognitive radio system, comprising:

• receiving an OFDMA-based signal by a receiver, the OFDMA-based signal comprising a preamble sequence that comprises band allocation information indicating information regarding a channel band allocated from a BS (base station) to a secondary user, wherein the allocated channel band comprises:
• a fraction of a broadcast channel band as the channel band for the CPE according to fractional bandwidth mode information, or
• bonding together a bundle of broadcast channel bands as the channel band for the CPE according to the channel bonding information, or
• a plurality of fractions of a broadcast channel bands as the channel band for the CPE according to the channel bonding information;
• and
• detecting the band allocation information based on the received OFDMA-based signal,
• wherein the allocated channel band is a channel band of unused channel bands having a bandwidth that is a natural number times a bandwidth resolution, the unused channel bands being channel bands among a range of frequencies allowed to but not used by a primary user, wherein the bandwidth resolution is a predetermined bandwidth smaller than a bandwidth of a broadcast channel band, wherein the allocated channel band is one of a broadcast channel band, a fraction of the broadcast channel band, and a channel band formed by bonding broadcast channel bands or a plurality of fractions of a broadcast channel band.