1. Date Submitted: [February 8, 2006]
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Suggested revisions for T/TR comments regarding CCA issues (Part 1)]
Date Submitted: [February 8, 2006]
Source: [Yihong Qi, Bin Zhen, Huan-Bang Li, Shinsuke Hara and Ryuji Kohno Company: National Institute of Information and Communications Technology ]
Contact: Yihong Qi
Voice: ,
Abstract: [Suggested revisions for T/TR comments regarding CCA with multiplexed preamble are presented.]
Purpose: [Help to resolve the T/TR comments on CCA issues]
Notice: This document has been prepared to assist the IEEE P It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.
Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P
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2. Suggested Revisions for T/TR Comments regarding CCA issues (Part 1)
Yihong Qi, Bin Zhen, Huan-Bang Li, Shinsuke Hara and Ryuji Kohno National Institute of Information and Communications Technology (NICT)
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3. Classification of the comments on CCA
T/TR comments on
clause 6.8a2.1: description of the multiplexed preamble (10, to be addressed in this presentation)
clause 6.9.9: CCA modes (to be completed soon)
E comments (3, all accepted)
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4. Comment 423 (TR) Comment Suggested remedy
The figure shows two blocks for the Frame Length, implying that the field is repeated twice (all 7 bits)
Suggested remedy
This should be the 4 lsbs of the Frame Length in the left most block the 3 msbs of the Frame Length field and the reserved bit in the next block over.
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5. Suggested revision for C423
The comment is accepted. Fig. 27b is revised as
Revised part
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6. Comment 424 (TR) Comment Suggested remedy
What is the "mandatory setting” on pp. 28, line 35
Suggested remedy
Define the "mandatory setting" clearly, perhaps with an xref to where it is defined.
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7. Suggested revision for C424
The comment is accepted. The sentence is revised as
``The modulation and the waveform of the inserted preamble symbols are defined in 6.8a.2 and 6.8a.3.”
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8. Comment 425 (TR) Comment Suggested remedy pp. 28, line 35
The numPSDUBits is only defined for when the mandatory data rate is used. There is no information for what to use for the other data rates.
Suggested remedy
Define numPSDUBits for the other data rates.
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9. Suggested revision for C425
The comment is accepted. The sentence ``the spreading code and PRF of inserted preamble…the numPSDUbits shall be 4.” is revised as
``The time interval between two adjacent inserted preamble symbols is fixed, and is equivalent to the duration of 4 mandatory symbol lengths. The mandatory symbol rate is 0.965MHz, as defined in 6.8a.3.1.”
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10. Comment 426 (TR) Comment Suggested remedy Comment accepted
pp. 28, line 41
You can't guarantee that the CCA detector will find the preamble symbols, it depends on the signal level, channel quality and interferers, if any..
Suggested remedy
Change "shall find at least" to be "will have the opportunity to find at least“
Comment accepted
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11. Comment 427 (TR) Comment Suggested remedy Comment accepted
pp. 29, line 6 (first line of the second paragraph)
I think you mean "command frame" not "MAC frame"
Suggested remedy
Change "MAC frame" to be "command frame“
Comment accepted
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12. Comment 428 (TR) Comment Suggested remedy
pp. 29, line 12 (the third paragraph)
Otherwise, the PHY is supposed to look for the preamble symbols, not report the medium idle. It only reports idle if it doesn't find the preamble symbols.
Suggested remedy
Change the text to correctly describe the CCA process.
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13. Suggested revision for C428
The comment is accepted. The sentences are revised as
``In the optional UWB CCA mode, the PHY shall listen to the medium during a period equivalent to the CCA detection window. If the preamble symbol is detected, the CCA shall report a busy medium. Otherwise, an idle medium shall be reported.”
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14. Comment 490 (T) Comment Suggested remedy
pp. 29, line 12 (the third paragraph)
The second to last paragraph in this section says, "Otherwise, an idle medium shall be reported". This sounds appropriate for mandatory ALOHA mode, but not for any other CCA mode.
Suggested remedy
Clarify text.
Comment accepted. Same comment as C428
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15. Comment 678 (T) Comment Suggested remedy
pp. 28, line 28 (the third paragraph of 6.8a2.1)
It is not clear to me how long the interleaved preamble segments should be. Figure 27b says "Preamble symbol" Does this mean one transmission one period of the preamble code? Later on in the text we have the following: "Wherever the CCA detection window starts, either from the regular preamble or from the data portion in a frame, the CCA detectors shall find at least 8 preamble symbols in the CCA detection window" How do we ensure this to be true. I'm thinking of small packets with very little payload?
Suggested remedy
Clarify the meaning of "Preamble Symbol" in terms of it length.
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16. Suggested revision for C678
The comment is accepted. The sentences are revised as (incorporating modification of fig.27b)
``Figure 27b shows the frame structure which supports the optional UWB CCA mode. The PSDU field of the frame originates from the MAC layer (5.4.3). The PHY of a transmitter periodically inserts one preamble symbol after each data segment of a fixed length in PHR and PSDU fields. The inserted preamble symbol is same as the preamble symbol used in the preamble field of the same frame, as defined in 6.8a.2. The first inserted preamble symbol shall be located immediately after the SHR.”
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17. Concluding Remarks
The revised suggestions for the comments regarding description of the multiplexed preamble are presented.
If the suggestions are acceptable, we are going to modify clause 6.8a.2.1 to incorporate those changes. The modified text will be sent to the web server soon.
Revisions corresponding to the remaining comments are to be presented next time.
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