1. HCCA TXOP handling difficulties
September 2004
HCCA TXOP handling difficulties
Jarkko Kneckt
Nokia
Jarkko Kneckt, Nokia

2. Scheduled APSD use with HCCA during CFP
September 2004
Scheduled APSD use with HCCA during CFP
HCCA can be used during contention free periods, CFP. The APSD instructions in sections and refer to operation in contention period, CP. The non-AP QSTA shall be able to use scheduled APSD power save with HCCA also during CFPs.
Jarkko Kneckt, Nokia

3. EOSP use in QoS-CF ACK frame, or with packed QoS+CF ACK frame
September 2004
EOSP use in QoS-CF ACK frame, or with packed QoS+CF ACK frame
, section j says: If the QAP does not receive an acknowledgement to a directed MPDU or management frame sent with the EOSP subfield set to 1, it shall retransmit that frame at least once within the same service period - subject to applicable retry or lifetime limit. Table 1 in page 22 lists QoS CF-ACK frame to data frame.
Can QoS Cf-ACK frame have set EOSP bit?
Must QoS Cf-ACK with set EOSP bit be acknowledged? With EDCA the EOSP bit can be set in Data and Null frames, which are acknowledged according to section , j).
Jarkko Kneckt, Nokia

4. EOSP and NAV/duration field dependence
September 2004
EOSP and NAV/duration field dependence
Does CF-ACK with set EOSP bit terminate both TXOP and HCCA service period? Or can terminal continue HCCA TXOP by transmitting a frame?
If EOSP terminates also the TXOP, should Duration / id field be set appropriately?
Jarkko Kneckt, Nokia

5. Q-ACK option and set EOSP in QoS Cf-POLL+CF-ACK frame
September 2004
Q-ACK option and set EOSP in QoS Cf-POLL+CF-ACK frame
Q-ACK option is used. QoS + CF POLL+CF ACK frame contains set EOSP bit. Does the EOSP bit refer to non-AP QSTA that transmitted QoS CF-poll frame or the non-AP QSTA from previous TXOP who is receiving QoS CF-ACK frame ?
QoS CF ACK +
CF-POLL,
EOSP == 1
QoS Data +
CF-Ack AP
SIFS
SIFS
QoS Data +
CF-Ack
Non-AP QSTA
TXOP with Non AP QSTA 2
TXOP with Non AP QSTA 1
Jarkko Kneckt, Nokia

6. Q-ACK option and set EOSP in QoS Cf-POLL+CF-ACK frame
September 2004
Q-ACK option and set EOSP in QoS Cf-POLL+CF-ACK frame
Clarification:
The EOSP bit terminates the stream that has appropriate TID. Thus, the stream that uses Q-Ack and scheduled power save does not receive EOSP bit in this scenario. -> Q-ACK and scheduled APSD cannot be used at the same time.
QoS CF ACK +
CF-POLL,
EOSP == 1
QoS Data +
CF-Ack AP
SIFS
SIFS
QoS Data +
CF-Ack
Non-AP QSTA
TXOP with Non AP QSTA 2
Jarkko Kneckt, Nokia

7. Can QoS +CF-Poll frame have set EOSP bit?
September 2004
Can QoS +CF-Poll frame have set EOSP bit?
What will be answer to transmitted QoS Cf-poll frame with set EOSP?
Must the QoS CF-Poll with set EOSP frame be acknowledged? AP
QoS CF-POLL,
EOSP = 1
Non- AP QSTA
Jarkko Kneckt, Nokia

8. September 2004
QoS Data + Cf-poll
The QoS Data + CF-Poll frame handling has allows terminal acknowledgement.
However with set EOSP bit in poll frame the non AP QSTA cannot transmit any traffic.
QoS Data + CF-POLL
EOSP = 1 AP
Non- AP QSTA
QoS CF-ACK
Jarkko Kneckt, Nokia

9. QoS Cf-ACK or “plain” ack use with scheduled APSD
September 2004
QoS Cf-ACK or “plain” ack use with scheduled APSD
Pages 98 –101 define possibilities to use TXOPs and different data flows for HCCA TXOP.
The QoS CF-ACK can contain EOSP bit to terminate scheduled APSD service period. It is vital that AP can use QoS CF-ACK freely when ever ACK or CF-ACK frame is transmitted.
The CF-ACK that is used in PCF. HCCA should not use the same frame to avoid confusions. Instead of CF-ACK the QoS+CF-ACK frame should be used in HCCA.
Jarkko Kneckt, Nokia

10. Block ACK operation in HCCA streams
September 2004
Block ACK operation in HCCA streams
If block ack is used in HCCA service period, is data flow as shown in figure 62.9 or will the data flow have a frame transmission by HC and after a SIFS by non-AP QSTA?
Jarkko Kneckt, Nokia

11. Block ACK aggregation rules for HCCA
September 2004
Block ACK aggregation rules for HCCA
Can block ack stream be aggregated with other streams? If it can, how aggregated no explicit acknowledgement streams and block ack streams are handled in the same service period.
The block ack does not react on the erroneous transmissions, just marks that the frame receiving of the frame is failed and sets the bit field to BA appropriately, while other ACK modes cannot continue the TXOP.
Jarkko Kneckt, Nokia