Method for transmitting control information

A method for transmitting control information, the method comprising:

• receiving, by a first narrowband user terminal of a plurality of narrowband user terminals, an extended physical broadcast channel, wherein the physical broadcast channel is extended by adding, by a base station, a position identifier indicating a time-frequency position of a common control channel domain, wherein the common control channel domain is divided into a plurality of narrowband sub-control channel domains, wherein the common control channel domain is an allocated time-frequency resource of a first size, and each of the plurality of the narrowband sub-control channel domains is an allocated time-frequency resource having a size that is smaller than the first size, the common control channel domain encompassing the plurality of the narrowband sub-control channel domains, and wherein the common control channel domain carries control information that is common to the plurality of narrowband user terminals;
• receiving, by the first narrowband user terminal, common control information on the common control channel domain according to the position identifier;
• initiating random access by the first narrowband user terminal;
• and
• after a connection is established between the first narrowband user terminal and a network, reporting, by the first narrowband user terminal, a channel quality state, and obtaining, by the first narrowband user terminal, a channel instruction, wherein the channel instruction is information used by the base station to instruct, according to a channel state of the each of the plurality of the narrowband sub-control channel domains, the first narrowband user terminal to select a narrowband sub-control channel domain of the plurality of the narrowband sub-control channel domains of the common control channel domain;
• and
• receiving, by the first narrowband user terminal on the selected narrowband sub-control channel domain of the common control channel domain, dedicated control information from the base station.

A base station, comprising:

• a processor, which is configured to:
• categorize downlink control information into common control information and dedicated control information;
• and
• a transmitter, which is configured to, before a connection is established between a first narrowband user terminal of a plurality of narrowband user terminals and a network, send, according to a position identifier in a physical broadcast channel, the common control information in each of a plurality of narrowband sub-control channel domains of a common control channel domain, wherein the physical broadcast channel is extended by adding the position identifier for indicating a time-frequency position of the common control channel domain, and the common control channel domain is divided into the plurality of narrowband sub-control channel domains, wherein the common control channel domain is an allocated time-frequency resource of a first size, and each of the plurality of narrowband sub-control channel domains is an allocated time-frequency resource having a size that is smaller than the first size, the common control channel domain encompassing the plurality of narrowband sub-control channel domains, and wherein the common control channel domain carries control information that is common to the plurality of narrowband user terminals;
• wherein the processor is further configured to allocate a random access resource dedicated for the first narrowband user terminal, to notify the first narrowband user terminal in system information, and after the connection is established, to select, according to a channel state of the each of the plurality of the narrowband sub-control channel domains, a narrowband sub-control channel domain with a channel state that complies with a set standard, for sending dedicated control information;
• wherein a channel instruction is used by the base station to instruct, according to the channel state of the each of the plurality of the narrowband sub-control channel domains, the first narrowband user terminal to select the narrowband sub-control channel domain that complies with the set standard;
• and
• wherein the processor is further configured to send the dedicated control information to the first narrowband user terminal using the selected narrowband sub-control channel domain of the common control channel domain.

A first narrowband user terminal, comprising:

• a transmitter;
• a receiver, configured to:
• receive an extended physical broadcast channel, wherein the physical broadcast channel is extended by adding, by a base station, of a position identifier indicating a time-frequency position of a common control channel domain, wherein the common control channel domain is divided into a plurality of narrowband sub-control channel domains, wherein the common control channel domain is an allocated time-frequency resource of a first size, and each of the plurality of the narrowband sub-control channel domains is an allocated time-frequency resource having a size that is smaller than the first size, and wherein the common control channel domain carries control information that is common to a plurality of narrowband user terminals;
• and
• to receive common control information on the common control channel domain according to a preset position identifier;
• and
• a processor coupled to the transmitter and the receiver and configured to:
• initiate random access;
• and
• after a connection is established with a network, to control the receiver to report a channel quality state, to obtain a channel instruction, wherein the channel instruction is information that instructs, according to a channel state of each of the plurality of narrowband sub-control channel domains, the first narrowband user terminal to select a narrowband sub-control channel domain of the common control channel domain;
• wherein the receiver is further configured to receive, on the selected narrowband sub-control channel domain of the common control channel domain, dedicated control information from the base station.