PSMP是一个802.11n中引入的action帧，属于管理帧，用来在各个STA之间共享AP通过EDCA获得的TXOP。
PSMP的payload,不包含MAC HEADER，有以下两个部分，一个是PSMP parameter set field, 一个是STA info field。
其中STA info filed是被触发(scheduled）的各STA的AID,以及各自的UTT and/or DTT时间分配。
STA可以分为三种类型：BC, MC, Individual。每一种有自己的STA info field格式。
PSMP parameter set field可以指定是否还有后续的PSMP frame，STA_info中有几个STA，以及本PSMP sequence的duration/id。
详细的格式如下：
filed category action PSMP parameter set STA info
length 1 1 2 8
value '7' ‘2’ - -
meaning HT PSMP indicators, utt/dtt allocation for each STA
PSMP parameter set格式如下：
fieldd N_STA MORE_PSMP PSMP sequence duration/id
length 5 1 10
value - - (8 us unit, max 8.184ms)
meaning number of sta in sta_info more PSMP PSMP sequence duration
STA info varaint for individual-addressed(IA):
filed STA_info type PSMP-DTT start offset PSMP-DTT duration STA_ID PSMP-UTT start offset PSMP-UTT duration reserved
length 2 11 8 16 11 10 6
value '0' (4us unit) (16us unit) AID (4us unit) (4us unit)
meaning IA relative to PSMP end relative to PSMP end
STA info varaint for multicast-:
filed STA_info type PSMP-DTT start offset PSMP-DTT duration Multicast_ID
length 2 11 8 43
value '1' (4us unit) (16us unit)
meaning multicast relative to PSMP end
STA info varaint for broadcast-:
filed STA_info type PSMP-DTT start offset PSMP-DTT duration reserved
length 2 11 8 43
value '2' (4us unit) (16us unit)
meaning broadcast relative to PSMP end