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Re: [STDS-802-16] Clarification on OFDMA TDD frame duration



Both methods are appropriate, but for different situations.  Method two would be the normal case where we have a detected, but uncorrectable bit error at the PHY level.  This will catch almost all errors and is not too difficult to implement in the MAC/PHY interface HW.  Method one is for the rare case where there was a bit error in the MAC error that was both undetected and uncorrected by the FEC at the PHY level.
 
Ken


From: owner-stds-802-16@listserv.ieee.org [mailto:owner-stds-802-16@listserv.ieee.org] On Behalf Of Avi Freedman
Sent: Friday, April 09, 2004 4:17 AM
To: STDS-802-16@listserv.ieee.org
Subject: Re: [STDS-802-16] Clarification on OFDMA TDD frame duration

Here is a question I received.  Does anyone have a good answer? 
Avi
 
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We are working on hardware implementation of the MAC802.16. As a member of this group, I am working on the TC (Transmission Convergence) Sublayer and MAC interface of MAC802.16. During reception of information from Physical layer, Physical layer reports the number of irrecoverable

Bytes of each FEC code word; I wish to know which of the following methods is suitable for implementation.



1. We can verify HCS of each header and extract the length field, then buffer the data according that length. If the HCS was wrong, in next FEC Code word, we check the TC pointer to find out the PDU location and decide based on it.



2. If the physical layer reports an irrecoverable, we have to discard the packet and the job is running till we receive a packet without an irrecoverable. Then we use this packet to find the start of the header using TC pointer and if the next packet was erroneous, we discard part of the PDU we saved before.



Best Regards,

Fahimeh Nouri