Wireless communication method using enhanced distributed channel access, and wireless communication terminal using same
Provided is a wireless communication terminal that communicates wirelessly. The wireless communication terminal includes a transceiver and a processor for processing a radio signal received through the transceiver or a radio signal to be transmitted through the transceiver. The processor accesses a channel according to according to a priority of data to be transmitted to the base communication terminal by the wireless communication terminal.
1. A wireless communication terminal that wirelessly communicates with a base wireless communication terminal, the wireless communication terminal comprising:
a transceiver; and
a processor,
wherein the processor is configured to:
transmit, to the base wireless communication terminal, a trigger-based physical layer protocol data unit (PPDU) using the transceiver,
switch a parameter set, which is a set of parameters used for the channel access, from a first parameter set to a second parameter set based on whether the base wireless communication terminal triggers a multi-user uplink transmission participation of the wireless communication terminal,
when a MAC protocol data unit (MPDU) included in the trigger-based PPDU does not request an immediate response, set a second parameter set timer for an access category of the MPDU when the transmission of the trigger-based PPDU ends,
when the MPDU included in the trigger-based PPDU requests the immediate response, set the second parameter set timer for the access category of the MPDU for which immediate response is received,
when the second parameter set timer expires, terminate an application of the second parameter set, and
access a channel according to a priority of data to be transmitted to the base communication terminal by the wireless communication terminal and the parameter set.
2. The wireless communication terminal of claim 1 , wherein the MPDU included in the trigger-based PPDU is a QoS data frame.
3. The wireless communication terminal of claim 1 , wherein the processor is configured to receive a beacon frame from the base wireless communication terminal and obtain information indicating a period of the second parameter set timer from the beacon frame.
4. The wireless communication terminal of claim 1 , wherein the processor is configured to calculate a random integer value within a contention window (CW),
set a backoff timer based on the random integer value, and
access the channel based on the back off timer and a predetermined slot time,
wherein the parameter set comprises a minimum value (CWmin) of the CW and a maximum value (CWmax) of the CW.
5. The wireless communication terminal of claim 1 , wherein the processor is configured to calculate a random integer value in a contention window (CW),
set a backoff timer based on the random integer value,
access the channel based on the back off timer and a predetermined slot time, and
if a value of the CW is greater than the maximum value (CWmax) of the CW according to a priority of the data to be transmitted, sets the value of the CW to the CWmax.
6. The wireless communication terminal of claim 1 , wherein the processor is configured to operate a plurality of queues that are classified according to an access category of data stored in a queue and performs backoff procedure of accessing a channel based on a time corresponding to a backoff timer in each of the plurality of queues, and
when there is no data stored in the queue and the backoff timer corresponding to the queue is 0, perform no operation at a slot boundary of the backoff timer,
wherein the backoff timer is set based on a random integer value calculated in a contention window (CW), and is reduced when the channel is idle for a predetermined slot time.
7. The wireless communication terminal of claim 6 , wherein when there is no data stored in the queue and the backoff timer corresponding to the queue is 0, the processor is configured to maintain the backoff timer to be 0.
8. An operation method of a wireless communication terminal that wirelessly communicates with a base wireless communication terminal, the method comprising:
transmitting a trigger-based physical layer protocol data unit (PPDU) to the base wireless communication terminal;
switching a parameter set, which is a set of parameters used for the channel access, from a first parameter set to a second parameter set based on whether the base wireless communication terminal triggers a multi-user uplink transmission participation of the wireless communication terminal;
when a MAC protocol data unit (MPDU) included in the trigger-based PPDU does not request an immediate response, setting a second parameter set timer for an access category of the MPDU when the transmission of the trigger-based PPDU ends;
when the MPDU included in the trigger-based PPDU requests the immediate response, setting the second parameter set timer for the access category of the MPDU for which immediate response is received;
when the second parameter set timer expires, terminating an application of the second parameter set;
accessing a channel according to a priority of data to be transmitted to the base wireless communication terminal and the parameter set; and
transmitting the data through the channel.
9. The method of claim 8 , wherein the MPDU included in the trigger-based PPDU is a QoS data frame.
10. The method of claim 8 , the method further comprising:
receiving a beacon frame from the base wireless communication terminal; and
obtaining information indicating a period of the second parameter set timer from the beacon frame.