Techniques relating to random access in a wireless communications network

A method of operating a wireless communications system comprising a user device and a base station, the method comprising:

• the base station periodically broadcasting system information on a physical broadcast channel;
• and
• the user device, when in an unconnected state with respect to the base station, participating in a random access procedure to seek to establish a connected state with respect to the base station,
• wherein the random access procedure comprises:
• the user device transmitting a random access preamble in accordance with parameters specified in the system information;
• in response to the random access preamble, the base station transmitting a random access response, wherein the random access response indicates an uplink grant allocated to the user device, the uplink grant comprising a first uplink resource allocated to the user device for a connection request message;
• in response to the random access response, the user device transmitting the connection request message via the first uplink resource;
• in response to the connection request message, the base station transmitting a contention resolution message;
• and
• in response to the contention resolution message, the user device transmitting an acknowledgement signal,
• wherein the system information periodically broadcast by the base station on the physical broadcast channel comprises an acknowledgement control marker, and
• wherein the user device:
• when the acknowledgement control marker is not set, transmits the acknowledgement signal on a reserved uplink control channel using a second uplink resource, and
• when the acknowledgement control marker is set, transmits the acknowledgement signal via the first uplink resource (i) allocated to the user device in the uplink grant and (ii) used for transmitting the connection request message in response to the random access response.

A base station for communicating with a user device in a wireless communications system,

• wherein the base station comprises one or more processors configured to:
• periodically broadcast system information on a physical broadcast channel, and;
• when in an unconnected state with respect to the user device, participate in a random access procedure to seek to establish a connected state with respect to the user device,
• wherein in the random access procedure, the one or more processors are configured to:
• listen for and receive a random access preamble transmitted by the user device in accordance with parameters specified in the system information;
• transmit a random access response in response to the random access preamble, wherein the random access response indicates an uplink grant allocated to the user device, the uplink grant comprising a first uplink resource allocated to the user device for a connection request message;
• listen for and receive the connection request message transmitted by the user device via the first uplink resource;
• transmit a contention resolution message in response to the connection request message;
• and
• listen for and receive an acknowledgement signal transmitted by the user device in response to the contention resolution message,
• wherein the system information periodically broadcast by the one or more processors on the physical broadcast channel comprises an acknowledgement control marker, and
• wherein the one or more processors are configured:
• when the acknowledgement control marker is not set, to listen for and receive the acknowledgement signal on a reserved uplink control channel using a second uplink resource, and
• when the acknowledgement control marker is set, to listen for and receive the acknowledgement signal via the first uplink resource (i) allocated to the user device in the uplink grant and (ii) used for receiving the connection request message in response to the random access response.

A method of operating a base station configured to communicate with a user device in a wireless communications system, the method comprising:

• periodically broadcasting system information on a physical broadcast channel;
• and
• when in an unconnected state with respect to the user device, participating in a random access procedure to seek to establish a connected state with respect to the user device,
• wherein the random access procedure comprises:
• listening for and receiving a random access preamble transmitted by the user device in accordance with parameters specified in the system information;
• transmitting a random access response in response to the random access preamble, wherein the random access response indicates an uplink grant allocated to the user device, the uplink grant comprising a first uplink resource allocated to the user device for a connection request message;
• listening for and receiving the connection request message transmitted by the user device via the first uplink resource;
• transmitting a contention resolution message in response to the connection request message;
• and
• listening for and receiving an acknowledgement signal transmitted by the user device in response to the contention resolution message,
• wherein the system information periodically broadcast by the base station on the physical broadcast channel comprises an acknowledgement control marker, and
• wherein the base station:
• when the acknowledgement control marker is not set, listens for and receives the acknowledgement signal on a reserved uplink control channel using a second uplink resource, and
• when the acknowledgement control marker is set, listens for and receives the acknowledgement signal via the first uplink resource (i) allocated to the user device in the uplink grant and (ii) used for receiving the connection request message in response to the random access response.

A user device for communicating with a base station in a wireless communications system,

• wherein the user device comprises one or more processors configured, when in an unconnected state with respect to the base station, to participate in a random access procedure to seek to establish a connected state with respect to the base station,
• wherein the one or more processors are configured to listen for and receive system information periodically broadcast on a physical broadcast channel by the base station,
• wherein, in the random access procedure, the one or more processors are configured to:
• transmit a random access preamble in accordance with parameters specified in the system information;
• listen for and receive a random access response transmitted by the base station in response to the random access preamble, wherein the random access response indicates an uplink grant allocated to the user device, the uplink grant comprising a first uplink resource allocated to the user device for a connection request message;
• transmit the connection request message via the first uplink resource;
• listen for and receive a contention resolution message transmitted by the base station in response to the connection request message;
• and
• transmit an acknowledgement signal in response to the contention resolution message,
• wherein the system information periodically broadcast by the base station on the physical broadcast channel comprises an acknowledgement control marker, and
• wherein the one or more processors are configured:
• when the acknowledgement control marker is not set, to transmit the acknowledgement signal on a reserved uplink control channel using a second uplink resource, and
• when the acknowledgement control marker is set, to transmit the acknowledgement signal via the first uplink resource (i) allocated to the user device in the uplink grant and (ii) used for transmitting the connection request message in response to the random access response.

A method of operating a user device configured to communicate with a base station in a wireless communications system, the method comprising:

• listening for and receiving system information periodically broadcast on a physical broadcast channel by the base station;
• and
• when in an unconnected state with respect to the base station, participating in a random access procedure to seek to establish a connected state with respect to the base station,
• wherein the random access procedure comprises:
• transmitting a random access preamble in accordance with parameters specified in the system information;
• listening for and receiving a random access response transmitted by the base station in response to the random access preamble, wherein the random access response indicates an uplink grant allocated to the user device, the uplink grant comprising a first uplink resource allocated to the user device for a connection request message;
• transmitting the connection request message via the first uplink resource;
• listening for and receiving a contention resolution message transmitted by the base station in response to the connection request message;
• and
• transmitting an acknowledgement signal in response to the contention resolution message,
• wherein the system information periodically broadcast by the base station on the physical broadcast channel comprises an acknowledgement control marker, and
• wherein the user device:
• when the acknowledgement control marker is not set, transmits the acknowledgement signal on a reserved uplink control channel using a second uplink resource, and
• when the acknowledgement control marker is set, transmits the acknowledgement signal via the first uplink resource (i) allocated to the user device in the uplink grant and (ii) used for transmitting the connection request message in response to the random access response.