Autonomous transmission for extended coverage

A base station node of a radio access network (RAN) which receives data on an uplink channel over an air interface from a user equipment unit, the base station node comprising:

• a transceiver configured to communicate over the air interface with the user equipment unit;
• a MAC-entity configured to operate for both a nominal mode and an extended mode with a synchronous HARQ protocol in which re-transmissions occur a fixed number of transmission time intervals after a previous transmission or re-transmission, and configured to make a selection between different modes of allocating data on the uplink channel, the MAC-entity being configured in accordance with the selection to allocate the data on the channel in:
• the extended mode in which the data is received in a pseudo transmission time interval, the pseudo transmission time interval comprising a first transmission time interval and a second transmission time interval, the second transmission time interval being consecutive and adjacent to the first transmission time interval, the first transmission time interval and the second transmission time interval each having a predetermined length equal the predetermined length of a single transmission time interval of the nominal mode, the nominal mode is one of the different modes of allocating data:
• an ACK/NACK generator for generating an acknowledgement message upon receipt of the data in the pseudo transmission time interval at a point in time at which the acknowledgement message would have been generated had a transmission time interval of the nominal mode instead been received,
• wherein in the extended mode, the base station node is configured to receive the data in the first transmission time interval and to re-receive the data in the second transmission time interval, wherein the data that is received in the first transmission time interval is the same as the data that is re-transmitted in the second transmission time interval.

A radio access network, comprising:

• a user equipment unit configured to transmit data and a base station node configured to receive the data transmitted from the user equipment unit,
• wherein the user equipment unit configured to operate with a synchronous HARQ protocol in which re-transmissions occur a fixed number of transmission time intervals after a previous transmission or retransmission and with capability of selectively sending the data on a channel using the synchronous HARQ protocol
• in an extended mode, the extended mode being one of two different modes for allocating data on the channel, wherein in the extended mode data is transmitted in a pseudo transmission time interval, the pseudo transmission time interval comprising a first transmission time interval and a second transmission time interval, the second transmission time interval being consecutive and adjacent to the first transmission time interval, the first transmission time interval and the second transmission time interval each having a predetermined length equal the predetermined length of a single transmission time interval of a nominal mode, the nominal mode one of the different modes of allocating data;
• and
• a base station node configured to communicate over an air interface with the user equipment unit, to receive the data on the channel either in the nominal mode or in the extended mode, and to generate an acknowledgement message upon receipt of the data in the pseudo transmission time interval at a point in time at which the acknowledgement message would have been generated had a transmission time interval of the nominal mode instead been received,
• wherein in the extended mode, the user equipment unit is configured to transmit the data in the first transmission time interval and to re-transmit the data in the second transmission time interval wherein the data that is transmitted in the first transmission time interval is the same as the data that is re-transmitted in the second transmission time interval, and
• wherein the second transmission time interval is prior to a receipt at the user equipment unit of an ACK/NACK from the base station node regarding the transmission of the data in the pseudo transmission time interval.

A method of operating a radio access network (RAN), the method comprising:

• transmitting data over an air interface from a user equipment unit to a base station node on a channel with a synchronous HARQ protocol in which re-transmissions occur a fixed number of transmission time intervals after a previous transmission or retransmission,
• selecting between different transmission modes and thereby sending data over the air interface using the synchronous HARQ protocol wherein upon the data being sent in
• an extended mode of the different transmission modes in which the data is transmitted in a pseudo transmission time interval, the pseudo transmission time interval comprising, a first transmission time interval and a second transmission time interval in which the data is re-transmitted, the second transmission time interval being consecutive and adjacent to the first transmission time interval, the first transmission time interval and the second transmission time interval having a predetermined length equal to the predetermined length of a single transmission time interval of a nominal mode, the nominal mode being one of the different transmission modes of allocating data, and
• receiving the data on the channel at the base station node either in the nominal mode or in the extended mode,
• wherein in the extended mode, the user equipment unit transmits the data in the first transmission time interval and re-transmit the data in the second transmission time interval, wherein the data that is transmitted in the first transmission time interval is the same as the data that is re-transmitted in the second transmission time interval, and
• wherein the second transmission time interval is prior to a receipt at the user equipment unit of an ACK/NACK from the base station node regarding the transmission of the data in the pseudo transmission time interval.

A user equipment unit comprising:

• a transmitter configured to communicate data to a base station of a radio access network over a radio interface;
• and
• a MAC-entity configured to allocate data on a channel in an extended mode in a pseudo transmission time interval,
• wherein the pseudo transmission time interval comprising a first transmission time interval and a second transmission time interval of essentially a same length, the first and second transmission times intervals being immediately adjacent of each other,
• wherein the data is transmitted initially in the first transmission time interval and thereafter is immediately re-transmitted in the second transmission time interval, wherein the data that is transmitted in the first transmission time interval is the same as the data that is re-transmitted in the second transmission time interval,
• wherein the second transmission time interval being prior to a receipt from the base station of an ACK/NACK regarding the pseudo transmission time interval,
• wherein the MAC-entity is configured to operate with the extended mode within a synchronous HARQ protocol in which re-transmissions occur a fixed number of transmission time intervals after a previous transmission or re-transmission.

A method of operating a user equipment (UE) configured to communicate with a radio base station (RBS) of a radio access network (RAN) over an air interface, the method comprising:

• determining, at the UE, to transmit data to the RBS in an extended mode, the extended mode one of two modes in which the UE can operate, the two modes further comprising a nominal mode;
• transmitting, from the UE to the RBS, a first block of the data in a first transmission time interval (TTI) of a fixed duration;
• and
• transmitting, from the UE to the RBS. a second block of the data in a second (TTI) of the fixed duration, the second TTI being immediately subsequent to the first TTI, wherein the UE operates within the extended mode with a synchronous HAW protocol in which re-transmissions occur a fixed number of TTIs after a previous transmission or re-transmission,
• wherein in response to the UE operating in the nominal mode, the first block of the data and the second block of the data are different blocks of the data, and
• wherein in response to the UE operating in the extended mode, the first block of the data and the second block of the data are a same block of the data in which the same data is transmitted at least twice within the same block such that a first portion of the block comprises a first transmission of the data and one or more subsequent portions of the block comprise a corresponding one or more re-transmissions of the data such that the entire same block is filled with the first transmission and each of the one or more retransmissions.

A method of operating a radio base station (RBS) of a radio access network (RAN) configured to communicate with a user equipment (UE) over an air interface, the method comprising:

• receiving, at the RBS, a first block of data transmitted from the UE in a first transmission time interval (TTI) of a fixed duration;
• receiving, at the RBS, a second block of data transmitted from the UE in a second (TTI) of the fixed duration, the second TTI being immediately subsequent to the first TTI;
• receiving, at the RBS, an indication from the UE of whether or not the first and second data blocks are to be combined;
• decoding, at the RBS, the first block of data and the second block of data based on the indication;
• and
• sending, from the RBS, an ACK/NACK to the UE based on the decoding,
• wherein the RBS operates with a synchronous HARQ protocol in which re-transmissions occur a fixed number of TTIs after a previous transmission or re-transmission, the first block of data and the second block of data received with the synchronous HARQ protocol, and
• wherein when the indication is that the first and second data blocks should be combined,
• the step of decoding the first block of data and the second block of data comprises combining the first block of data and the second block of data, and decoding the combined block, in which the same data is transmitted at least twice within the same block such that a first portion of the block comprises a first transmission of the data and one or more subsequent portions of the block comprise a corresponding one or more re-transmissions of the data such that the entire same block is filled with the first transmission and each of the one or more retransmissions, and
• the step of sending the ACK/NACK comprises sending the ACK/NACK based on the decoding of the combined block.