System and method for selecting unlicensed frequency band using hybrid TDD and FDD

A frequency allocation method for TDD-based wireless communication between a base station and at least two terminals through at least a first frequency of a whitespace, comprising:

• detecting, by at least two terminals, a receivability of downstream data from a base station through a first frequency and a second frequency of a whitespace at a site of one of the at least two terminals, wherein the second frequency is not whitespace at the site of the one of the at least two terminals;
• sending, by the at least two terminals, information of downstream quality of the first frequency and the second frequency which is a detection result of the detecting to the base station through the first frequency;
• receiving, by the base station, the information of downstream quality and retaining the information along with an identifier of the at least two terminals and a frequency in which the detection result was obtained;
• transmitting, by the at least two terminals, a required quality for reception of the downstream data before the reception of the downstream data;
• receiving, by the base station, the required quality from a respective terminal of the at least two terminals;
• selecting, by the base station, at least one frequency satisfying the required quality by reference to the information of downstream quality and allocating the one frequency as a frequency for use in data transmission to the respective terminal;
• sending, by the base station, an allocation result of the allocating to the respective terminal,
• accessing, by the base station, a database to acquire a list of usable frequencies;
• and
• transmitting, by the base station, periodically specific signals for the detection result of the detecting through the first and the second frequency, wherein the second frequency is chosen from frequencies outside whitespace at a site of one terminal and available for another terminal;
• wherein in accordance with the allocation result, the base station and at least one terminal configure a one-way link in the first frequency or the second frequency.

A frequency allocation method for TDD-based wireless communication through at least a first frequency of a whitespace, comprising:

• receiving, by a base station, information of downstream quality of the first frequency and the second frequency and retaining the information along with an identifier of at least two terminals that sent the information of the downstream quality and a frequency of which a detection result was obtained by the at least two terminals;
• transmitting, by the at least two terminals, a required quality for reception of the downstream data before the reception of the downstream data;
• receiving, by the base station, a required quality for reception of the downstream data before the reception of the downstream data from a respective terminal of the at least two terminals;
• selecting, by the base station, at least one frequency satisfying the required quality by reference to the information of downstream quality and allocating the one frequency as a frequency for use in data transmission to the respective terminal;
• sending, by the base station, an allocation result of the allocating to the respective terminal,
• accessing, by the base station, a database to acquire a list of usable frequencies;
• and
• transmitting, by the base station, periodically specific signals for the detection result of the detecting through the first and the second frequency, wherein the second frequency is chosen from frequencies outside whitespace at a site of one terminal and available for another terminal;
• wherein in accordance with the allocation result, configuring by at least the base station a one-way link in the first frequency or the second frequency.

A frequency allocation method for TDD-based wireless communication through at least a first frequency of a whitespace, comprising:

• detecting, by at least two terminals, a receivability of downstream data from a base station through a first frequency and a second frequency of a whitespace at a site of one of the at least two terminals, wherein the second frequency is not whitespace at the site of the one of the at least two terminals;
• sending, by the at least two terminals, information of downstream quality of the first frequency and the second frequency which is a detection result of the detecting to the base station through the first frequency;
• and
• transmitting, by the at least two terminals, a required quality for reception of the downstream data before the reception of the downstream data;
• wherein the base station is configured to:
• receive the information of the downstream quality of the first frequency and the second frequency,
• retain the information therein along with an identifier of the at least two terminals and a frequency in which the detection result at the first step has was obtained,
• receive, by the base station, a required quality for reception of the downstream data before the reception of the downstream data from a respective terminal of the at least two terminals,
• select at least one frequency satisfying the required quality by reference to the information of downstream quality and allocating the one frequency as a frequency for use in data transmission to the respective terminal,
• send an allocation result of the allocating to the respective terminal,
• access a database to acquire a list of usable frequencies, and
• transmit periodically specific signals for the detection result of the detecting through the first and the second frequency, wherein the second frequency is chosen from frequencies outside whitespace at a site of one terminal and available for another terminal;
• and
• wherein, in accordance with the allocation result, configuring by at least one terminal a one-way link in the first frequency or the second frequency.