Section: 5.4.7.2 Maintenance of PUR Uplink Time Alignment
Content: MAC entity may be configured with timer pur-TimeAlignmentTimer by upper layers as specified in TS 36.331[ Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC); Protocol specification ]  [8], clause 5.3.8.3. The MAC entity shall: - when pur-TimeAlignmentTimer configuration is received from upper layers: - start or restart pur-TimeAlignmentTimer. - when pur-TimeAlignmentTimer is released by upper layers: - stop the pur-TimeAlignmentTimer, if running. - when a Timing Advance Command MAC control element is received or PDCCH indicates timing advance adjustment as specified in TS 36.212[ Evolved Universal Terrestrial Radio Access (E-UTRA); Multiplexing and channel coding ]  [5] and if a NTA has been stored or maintained: - if the Timing Advance Command MAC control element or PDCCH indicating timing advance adjustment is addressed with a PUR-RNTI: - apply the Timing Advance Command or the timing advance adjustment; - start or restart the pur-TimeAlignmentTimer, if configured; - indicate to upper layers that the Timing Advance value has been adjusted. - upon considering a Random Access procedure successfully completed: - start or restart the pur-TimeAlignmentTimer, if configured; - indicate to upper layers that the Timing Advance value has been adjusted; - if a temporary NTA has been stored, delete the stored temporary NTA. - upon considering a Random Access procedure unsuccessfully completed, if a temporary NTA has been stored: - set the NTA to the stored temporary NTA; - delete the stored temporary NTA. Upon request from upper layers, MAC entity shall indicate whether pur-TimeAlignmentTimer is running.