lisecond of resources to the mobile. Process Transmission instants of data on PUSCH physical channel number Reception instants of ACK/NACK on PHICH physical channel Figure 4.12. HARQ function in the FDD mode Data transfer for uplink. For a color version of the figure, see www.iste.co.uk/perez/volte.zip For the TDD mode, the HARQ process number, under the HARQ entity, depends on the type of configuration of the time frame and transmission mode (Table 4.7). Radio Interface Procedures 139 Configuration of the time frame 00123456 Number of sub-frames / uplink Transmission mode 1 042321 Transmission mode 2 Table 4.7. HARQ process number in the TDD mode Data transfer for uplink The shift which is given in milliseconds, between the transmission of a block in the PUSCH physical channel and the reception of the HI indicator in the PHICH physical channel, is shown in Table 4.8. Number of the sub frame having received HI Configuration of the time frame Table 4.8. Shift between the PUSCH and PHICH physical channels Figure 4.13 describes the HARQ mechanism for configuration 1 of the time frame in the TDD mode. 140 VoLTE and ViLTE Transmission instants of data on PUSCH physical channel Sub-frame number Reception instants of ACK/NACK on PHICH physical channel process number Figure 4.13. HARQ function in the TDD mode, for configuration 1 Data transfer for uplink. For a color version of the figure, see www.iste.co.uk/perez/volte.zip The transport block transmitted in sub-frame 2 or 7 (sub-frame 3 or 8 respectively) receives the HI indicator with a shift of 4 milliseconds (6 milliseconds respectively). Under a HARQ process, if a transport block is acknowledged, a new transport block can be transmitted 10 milliseconds later. If a transport block is not acknowledged, the RV1 redundancy version is transmitted 10 milliseconds later. 4.2.2.4.2. Data transfer for downlink Contrary to the uplink, a single HARQ entity is developed independently of the transmission mode. In case of the aggregation of radio channels, a HARQ entity is develo