Medium Access Control (MAC) and Physical Layer (PHY) - CISE

4-June-07 P1901_PRO_016_r0
1
Send CE frame next=1
in Data Token
Slave initiated
2
Master
Allow CE frame=1
in Data Token
Slave
CE frame
3
4
Unicast Bit-loading
table
for uplink
CE=Channel Estimation
Allow CE frame=1
in Data Token
Master initiated
Submission page 98 UPA-OPERA
1
Master
Slave
CE frame
2
Figure 31 Transmission of channel estimation frames by TDRs and CPEs
� Channel estimation initiated by the slave:
3
Unicast Bit-loading
table
for uplink
A slave shall periodically evaluate that it is time to send a new channel estimation frame. A slave shall not ask
permission to send a channel estimation frame more than once every MIN_INTERVAL_FOR_CE_REQUESTS
(default value is 3 seconds and corresponds to the minimum number of seconds between two requests from the
same slave for an uplink channel estimation).
A slave may ask permission to send a channel estimation frame by setting the “Send Channel Estimation Frame
Next” to 1 in the data token to its master. The master may accept or reject this request by setting the “Allow
Channel Estimation Frame” to 1 (Accept) or 0 (Reject) in the next data token it returns to this slave. Upon
reception of a data token with “Allow Channel Estimation Frame” set to 1, the slave shall transmit a Channel
Estimation Frame. At the end of the transmission the slave shall enter reception mode, and the next transmitter
will be the master.
� Channel estimation initiated by the master:
The channel estimation process also allows the master for asking the slave to send a channel estimation frame.
In this case, the master directly sets the “Allow Channel Estimation” to 1 in the data token sent to the slave. The
process is then executed in the same way as mentioned above.
A master may request a slave to transmit a Channel Estimation frame as often as it deems necessary.