Methods and apparatus for handling mtc long drx cycle/sleep lengths

Abstract

Current wireless networks do not allow machine type communication (MTC) devices to have long discontinuous reception (DRX) cycles or sleep lengths. A long DRX cycle may allow MTC systems and devices to operate with much longer DRX/Sleep cycles/periods. This may facilitate the MTC operations for infrequent system access or infrequent system reaching (e.g. paged once in a week) with no or low mobility and may allow MTC devices to sleep for a long time with low power consumption.

What is claimed: 
     
         1 . A WTRU, the WTRU comprising:
 a processor, the processor being configured to:
 determine a cycle base unit type and a length of a long discontinuous reception (DRX) cycle; 
 generate a number of base units of the cycle base unit type using the length of the long DRX cycle; and 
 generate the long DRX cycle from the number of base units. 
   
     
     
         2 . The WTRU of  claim 1 , wherein the cycle base unit type is an extended subframe number (SFN) cycle type. 
     
     
         3 . The WTRU of  claim 2 , wherein the processor is configured to generate the number of base units of the cycle base unit type using the length of the long DRX cycle by:
 determining n number of SFN cycles to be used for an extended SFN cycle type base unit; and   generating a number of extended SFN cycles needed to make up the length of the long DRX cycle, wherein each extended SFN cycle in the number of extended SFN cycles comprises n number of SFN cycles.   
     
     
         4 . The WTRU of  claim 3 , wherein the processor is configured to generate the long DRX cycle from the number of base units by generating the long DRX cycle from the number of extended SFN cycles. 
     
     
         5 . The WTRU of  claim 1 , wherein the cycle base unit type is a time unit type. 
     
     
         6 . The WTRU of  claim 5 , wherein the processor is configured to generate the number of base units of the cycle base unit type using the length of the long DRX cycle by:
 determining a length of time for the time unit type;   determining a number of time units needed to make up the length of the long DRX cycle;   generating the number of time units, wherein each time unit in the number of time units comprises the length of time for the time unit type.   
     
     
         7 . A wireless transmit/receive unit (WTRU) for determining when to receive a signal, the WTRU comprising:
 a processor, the processor being configured to:
 determine a system frame number cycle number (SCN) within a total DRX period; 
 determine a long DRX cycle length; and 
 generate an offset SCN using the SCN and the long DRX cycle length. 
   
     
     
         8 . The WTRU of  claim 7 , wherein the processor is further configured to determine a page timing using the offset SCN. 
     
     
         9 . The WTRU of  claim 8 , wherein the processor is further configured to receive a paging signal from a network using the page timing. 
     
     
         10 . The WTRU of  claim 7 , wherein the processor is further configured to:
 determine a number of short DRX cycles to be used to receive a signal; and   schedule a long DRX cycle using the offset SCN and the long DRX cycle length.   
     
     
         11 . The WTRU of  claim 10 , wherein the processor is further configured to schedule the number of short DRX cycles within the long DRX cycle using the short DRX cycle length. 
     
     
         12 . The WTRU of  claim 10 , wherein the processor is further configured to schedule the number of short DRX cycles before the long DRX cycle using the short DRX cycle length. 
     
     
         13 . The WTRU of  claim 10 , wherein the processor is further configured to schedule the number of short DRX cycles after the long DRX cycle using the short DRX cycle length. 
     
     
         14 . The WTRU of  claim 7 , wherein the processor is further configured to:
 determine a number of short DRX cycles to be used to receive a signal;   schedule a first long DRX cycle and a second long DRX cycle using the offset SCN and the long DRX cycle length; and   schedule the number of short DRX cycles between the first long DRX cycle and the second long DRX cycle.   
     
     
         15 . A wireless transmit/receive unit (WTRU) for minimizing clock drift impact, the WTRU comprising:
 a processor, the processor configured to:
 determine a long sleep length, a clock drift rate for a WTRU, and a wake-up time; and 
 generate an adjustment window using the long sleep length, the clock drift rate, and the wake-up time. 
   
     
     
         16 . The WTRU of  claim 15 , wherein the processor is further configured to receive a signal from a network using the adjustment window. 
     
     
         17 . The WTRU of  claim 15 , wherein the processor is configured to generate the adjustment window using the long sleep length, the clock drift rate, and the wake-up time by:
 determining the adjustment window using the long sleep length;   scheduling the adjustment window using the wake-up time;   adjusting the adjustment window using the clock drift rate such that a signal may be received from a network during the adjustment window.   
     
     
         18 . The WTRU of  claim 15 , wherein the processor is further configured to determine a clock drift direction. 
     
     
         19 . The WTRU of  claim 18 , wherein the processor is configured to generate the adjustment window using the long sleep length, the clock drift rate, and the wake-up time by:
 determining the adjustment window using the long sleep length;   scheduling the adjustment window using the wake-up time;   decreasing a length of the adjustment window using the clock drift rate when the clock drift direction indicates that a clock is drifting towards longer time.   
     
     
         20 . The WTRU of  claim 18 , wherein the processor is configured to generate the adjustment window using the long sleep length, the clock drift rate, and the wake-up time by:
 determining the adjustment window using the long sleep length;   scheduling the adjustment window using the wake-up time;   increasing a length of the adjustment window using the clock drift rate when the clock drift direction indicates that a clock is drifting towards shorter time.   
     
     
         21 . A WTRU comprising:
 a processor, the processor configured to:
 receive a first system frame number (SFN) cycle order number from a network; 
 determine a second SFN cycle order number; and 
 calculate a drift range using the first SFN cycle order number and the second SFN cycle order number. 
   
     
     
         22 . The WTRU of  claim 21 , wherein the processor is configured to receive the first SNF cycle order number from the network via a system information. 
     
     
         23 . The WTRU of  claim 21 , wherein the processor is further configured to align a local SFN cycle number with the first SFN cycle order number when the drift range indicates that first SFN cycle order number and the second SFN cycle order number are not aligned. 
     
     
         24 . The WTRU of  claim 23 , wherein the processor is further configured to determine a time to receive a signal from the network using the aligned SFN cycle number. 
     
     
         25 . The WTRU of  claim 21 , wherein the processor is further configured to receive a signal from the network in a next SFN cycle when the drift range indicates the network is scheduled to transmit the signal in the next SFN cycle.