Slot bundling
Systems and methods to bundle mini-slots in an OFDM based wireless communication system. Mini-slots are bundled to improve the probability of successful reception by Permitting repeated transmission of a given transport block of data. Mini-slots which are contiguous or non-contiguous in time and/or frequency may be bundled, and mini-slots from different slots may also be bundled.
1. A method of downlink data transmission from a base station to a User Equipment (UE) in a cellular communication system utilizing an Orthogonal Frequency Division Multiplexing (OFDM) modulation format, the method comprising steps of:
scheduling transmission of a Transport Block of data in a first mini-slot comprising at least one OFDM symbol defined within a slot of an OFDM transmission format;
scheduling at least one repeated transmission of the Transport Block of data in at least one subsequent mini-slot comprising at least one OFDM symbol;
transmitting an indication of the scheduling from the base station to the UE; and
transmitting the Transport Block as defined by the scheduling from the base station to the UE wherein a first and at least one subsequent mini-slots are located in different slots, wherein a number of repetitions is transmitted from the base station to the UE in a Radio Resource Control (RRC) message, wherein the repeated transmissions use different redundancy versions of the same Transport Block, wherein the transmission of different redundancy versions is configured by physical layer signalling, and wherein the indication of scheduling is transmitted in the first mini-slot.
2. The method according to claim 1 , wherein the RRC message further indicates whether the at least one repeated transmission is the same or a different redundancy version.
3. The method according to claim 1 , wherein the first and at least one subsequent mini-slots start at the same time, but utilize different frequency resources.
4. The method according to claim 1 , wherein the first and at least one subsequent mini-slots start at different times.
5. The method according to claim 4 , wherein the first and at least one subsequent mini-slots use the same frequency resources.
6. The method according to claim 4 , wherein the first and at least one subsequent mini-slots use different frequency resources.
7. The method according to claim 1 , wherein the first and at least one subsequent mini-slots are located in the same slot.
8. The method according to claim 7 , wherein the indication of scheduling is transmitted in a DCI message on the PDCCH transmitted in the first mini-slot.
9. The method according to claim 1 , wherein the indication of scheduling is transmitted in a DCI message on a PDCCH of a slot.
10. The method according to claim 1 , wherein the UE is configured to transmit an ACK signal if a mini-slot is successfully decoded, and wherein the base station does not transmit further scheduled repetitions of that mini-slot after receipt of the ACK.
11. The method according to claim 1 , wherein the UE is configured to only transmit a NAK signal if a mini-slot has not been successfully decoded after all repetitions of that mini-slot have been received.
12. A method of uplink data transmission from a UE to a base station in a cellular communication system utilizing an Orthogonal Frequency Division Multiplexing (OFDM) modulation format, the method comprising the steps of:
scheduling transmission in accordance with available resources of a Transport Block of data in a first mini-slot comprising at least one OFDM symbol defined within a slot of an OFDM transmission format;
scheduling at least one repeated transmission in accordance with available resources of the Transport Block of data in at least one subsequent mini-slot comprising at least one OFDM Symbol; and
transmitting the Transport Block as defined by the scheduling from the UE to the base station;
wherein the repeated transmissions use different redundancy versions of the same Transport Block, wherein the transmission of different redundancy versions is configured by physical layer signalling, and wherein the indication of scheduling is transmitted in a DCI message on a PDCCH of the slot in which at least the first mini-slot is located.
13. The method according to claim 12 , wherein a number of repetitions is transmitted from the base station to the UE in a Radio Resource Control (RRC) message.
14. The method according to claim 12 , wherein the RRC message further indicates whether the at least one repeated transmission is the same or different redundancy version.
15. The method according to claim 14 , wherein the first and at least one subsequent mini-slots use the same frequency resources.
16. The method according to claim 12 , wherein the first and at least one subsequent mini-slots start at different times.
17. The method according to claim 12 , wherein the first and at least one subsequent mini-slots are located in different slots.