Re: [802.19] Request for suggestions to make 19-15-0063 better!
Alireza,
I agree with your intent, and general direction.
I would add, however, that I can see a reasonable case for an UL mechanism
which is both scheduled and "protected" in some fashion so as to be part of
the same TxOP of a DL, where the DL did the category 4 LBT. This would
analogous to several mechanisms in 802.11 itself, where "responding" STAs
can transmit a SIFS after an enabling/triggering reception. The challenge
is that if the LAA transmissions can't be back-to-back with no gap (and I
suspect back-to-back might be a challenge for LAA?) then the medium would
need to be managed so that the overlapping 802.11 system doesn't see idle
medium and get confused that the TxOP is complete.
So, can we say that UL should either use (consider) category 4 LBT, or a
mechanism which creates a "TxOP continuation" on the medium. (And, of
course, our suggested limits on maximum TxOP time would still apply.)
Mark
-----Original Message-----
From: Alireza Babaei [mailto:A.Babaei@xxxxxxxxxxxxx]
Sent: Tuesday, August 04, 2015 4:59 PM
To: STDS-802-19@xxxxxxxxxxxxxxxxx
Subject: Re: [802.19] Request for suggestions to make 19-15-0063 better!
Hi Andrew,
Thanks again for putting together this presentation. I have a comment
regarding the LBT requirements in UL LAA. So far, only LAA DL transmissions
is recommended to use LBT category 4 in 3GPP. For UL, LBT is recommended,
without specifying which category. In fact, it has been the intention of
3GPP to use different LBT category for UL from DL. In 3GPP TR 36.889, §9,
Conclusion:
"Based on the evaluations and findings in Section 8, it is recommended that
the channel access framework defined in section 7.2.1.6 be adopted for LAA.
The channel access framework includes a category 4 LBT scheme including
random backoff and variable contention windows at least for the downlink
data transmissions. It is recommended that the key parameters of the LBT
scheme such as contention windows and defer periods should be configurable
within limits to enable fair coexistence with other technologies operating
in unlicensed spectrum. It is recommended that LAA supports uplink LBT at
the UE. In LAA systems, where the UE¹s uplink transmissions are controlled
by the eNB, the uplink channel access scheme can be different from the
downlink channel access scheme for an LAA SCell."
§7.2.1.6:
"It is recommended that a Category 4 LBT mechanism is the baseline at least
for LAA DL transmission bursts containing PDSCH.
It is recommended that LAA supports uplink LBT at the UE. The UL LBT scheme
can be different from the DL LBT scheme (e.g. by using different LBT
mechanisms or parameters) for example, since the LAA UL is based on
scheduled access which affects a UE¹s channel contention opportunities.
Other considerations motivating a different UL LBT scheme include, but are
not limited to, multiplexing of multiple UEs in a single subframe. The
candidates for DL and UL LBT that have been considered in the study item for
the case where LAA supports both DL and UL transmissions are listed in
Section 8.3.2.2."
3GPP is arguing that LBT category 4 should not be used for UL LAA because it
affects LAA eNB UL scheduling. On the other hands, similar arguments in
favor of an exponential backoff mechanism holds for both UL and DL LAA
transmissions. I recommend to add a proposal that LBT category 4 be
considered for UL LAA as well.
Regards,
Alireza
On 8/2/15, 11:18 PM, "Andrew Myles (amyles)" <amyles@xxxxxxxxx> wrote:
>G'day all
>
>As promised the latest version is at
>https://mentor.ieee.org/802.19/dcn/15/19-15-0063-04-0000-proposal-for-i
>eee
>-802-submission-to-3gpp.pptx
>
>Comments welcome ... and thanks to all those that have provided
>comments so far. The comments have made the document much better! :)
>
>It is still a little long but it is structured in a way that means it
>can be presented in a time that represents the time available
>
>Andrew
>
>-----Original Message-----
>From: Andrew Myles (amyles)
>Sent: Monday, 3 August 2015 1:11 PM
>To: 'yamadaakira@xxxxxxxxxxxxx'; STDS-802-19@xxxxxxxxxxxxxxxxx
>Subject: RE: [802.19] Request for suggestions to make 19-15-0063 better!
>
>G'day Akira
>
>Done! Thanks for your input
>
>I will upload a new version later today (my time)
>
>Andrew
>
>
>-----Original Message-----
>From: Akira Yamada [mailto:yamadaakira@xxxxxxxxxxxxx]
>Sent: Friday, 31 July 2015 5:41 PM
>To: STDS-802-19@xxxxxxxxxxxxxxxxx; Andrew Myles (amyles)
>Subject: Re: [802.19] Request for suggestions to make 19-15-0063 better!
>
>Dear Andrew-- I appreciate your creating great presentation material
>for the upcoming LAA workshop.
>
>Regarding my comment in the previous teleconference on TxOP duration in
>slide p34, please refer to the Section 4.3.2 in TR36.889-d00. Burst
>transmission duration (=TxOP) in Japanese regulation is limited <
>4.0ms, to enable co-existance among several systems in 5GHz band. It looks
"4ms"
>is the most severe rule compared with other countries.
>That's why 3GPP simulates co-ex using TxOP < 4ms. Then, I would suggst
>change "5ms" to "4ms" in slide P34. Please let me know if there's any
>concern.
>
>Best Regards
>Akira
>
>Akira Yamada
>Research Laboratories, NTT DOCOMO,INC.
>TEL:+81-46-840-3759
>
>
>
>On 2015/07/28 14:00, Andrew Myles (amyles) wrote:
>> G'day all
>>
>> The latest version of the proposed 802 submission to the 3GPP
>> workshop is
>>
>>https://mentor.ieee.org/802.19/dcn/15/19-15-0063-03-0000-proposal-for-
>>iee
>>e-802-submission-to-3gpp.pptx.
>> Thank you to those who provided comments
>>
>> Roger, I will be attending the 802.19 call but may be a couple of
>> minutes late
>>
>> Andrew
>>
>> *From:*Andrew Myles (amyles)
>> *Sent:* Tuesday, 21 July 2015 12:22 PM
>> *To:* STDS-802-19@xxxxxxxxxxxxxxxxx
>> *Subject:* [802.19] Request for suggestions to make 19-15-0063 better!
>>
>> G'day all
>>
>> Last week I presented
>> https://mentor.ieee.org/802.19/dcn/15/19-15-0063-00-0000-proposal-for
>> - ieee-802-submission-to-3gpp.pptx as the basis of a possible
>> submission from IEEE 802 to the 3GPP Workshop at the end of August.
>> Many people provided excellent comments and suggested refinements
>> during the meeting. As requested, some people have sent me their
>> comments via e-mail. However, many have not yet done so. Please send
>> me any comments or suggestions so that I can incorporate them into
>> the next version for discussion at the upcoming
>> 802.19 WG teleconferences. And on that topic, could someone please
>> send out details for the scheduled teleconferences; when, where and how?
>>
>> Steve, the draft minutes are incorrect. The session at which "/Jingyi
>> Zhou and Mingxi Fan presented a Liaison presentation on LTE-U, in
>> document 802.19/15-57r1/." was held on Tuesday, 14 July and not
>> Wednesday, 15 July.
>>
>> Andrew
>>