RE: stds-80220-requirements: 4.1.9 Latency- ARQ loop delay

[Li Junyi <Junyi_Li@flarion.com>]

Jin,

 

I am a little puzzled by your estimation. Note that when a physical frame is transmitted, it is also received at the same time. Unless the receiver has to take the entire time duration of a physical frame to finish the decoding after the frame has been received, the ARQ loop delay seems to be dominated by the two TX physical frames, not four.

 

In addition, the use of small frame size is not uncommon in other technologies. For example, in HDR, the slot time is 1.66ms. Voice traffic often has delay constraint of 20 or 40 ms. Considering the scheduling jitter and retransmission requirement, 10 ms ARQ loop delay does not seem to be terribly small.

 

Regards,

 

Junyi

 

-----Original Message-----
From: Marianna Goldhammer [mailto:marianna.goldhammer@alvarion.com]
Sent: Thursday, October 30, 2003 8:05 AM
To: Jin-Weon Chang; stds-80220-requirements@ieee.org
Subject: RE: stds-80220-requirements: 4.1.9 Latency- ARQ loop delay

 

Jin,

 

I agree with your comments.

 

In my understanding, video teleconf needs the lowest delay, I guess

 that 40-50ms for ARQ loop delay should be enough.

 

Regards,

 

Marianna

-----Original Message-----
From: Jin-Weon Chang [mailto:jwchang1@samsung.com]
Sent: Thursday, October 30, 2003 4:16 AM
To: stds-80220-requirements@ieee.org
Subject: stds-80220-requirements: 4.1.9 Latency- ARQ loop delay

Dear colleagues,

 

In the section 4.1.8 Latency "ARQ loop delay" is required to be less than 10ms.

If I understand the ARQ loop delay correctly, it includes

- TX time of a physical frame,

- Propagation time over the air,

- RX time of a physical frame,

- Processing time for acknowledgement,

- TX time of a ACK/NACK frame,

- Propagation time over the air, and

- RX time of an ACK/NACK frame.

ARQ loop delay includes 4 times of physical frame

if we assume ACK/NACK information is transffered in a physical frame.

Limiting the delay within 10ms results in limiting the size of a physical frame

less than 2.5ms.

This requirement will highly restrict physical design of MBWA.

I think the size of a physical frame should be determined

considering not only delay factor but also many other factors.

 

Thus I would like to propose that 10ms requirement in ARQ loop delay be removed.

 

Best regards,

Jin

 

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