FIG. 8 is a schematic diagram illustrating subframe 800. The subframe 800 may include two slots, each having a length of about 0.5 milliseconds, and including seven symbols. According to one embodiment, the second half of the last symbol 820 may be punctured to provide the receiving UE at least 33.33 microseconds of guard interval as the Tx/Rx switching time.

In various embodiments, a UL-DMRS may be transmitted in the first symbol 810 in addition to those UL-DMRS transmitted in the fourth symbol 830 and the eleventh symbol 840 of the subframe 800. In one embodiment, the base sequence and cyclic shift used for the UL-DMRS on the first symbol 810 may be the same as those used for the UL-DMRS on the fourth symbol 830 or the eleventh symbol 840.

In some embodiments, depending on the time required for setting up AGC, the first symbol 810 may be generated by mapping a regular UL-DMRS to the subcarriers. In this case, the subframe 800 may provide about 71.37 microseconds (e.g., 66.67 μs of the first symbol, plus 4.7 μs of the normal CP provided for the second symbol) for the AGC setting time at the receiver. In some embodiments, the first half of the first symbol 810 may be punctured, instead of or in addition to the last symbol 820 being punctured, to provide additional guard period for handling the Tx/Rx switching time. In other embodiments, the puncturing of the first symbol 810 may not be necessary if the guard period is accommodated via partial or full puncturing of the last symbol 820.