G’day all
Action: request for volunteers to lead discussions on each issue in most recent 3GPP RAN1 response
In July 2016, IEEE 802 sent 3GPP RAN1 a
liaison related to outstanding comments on LAA Rel. 13 from a previous liaison exchange. In late November 2016, 3GPP RAN1 finally
responded. The 3GPP RAN1 liaison also included a response to a
liaison from IEEE 802 sent in November 2016 related to energy thresholds
In January 2017, IEEE 802.19 WG and IEEE 802.11 PDED ad hoc will consider various aspects of the most recent 3GPP RAN1 response. The discussions in January will go much more efficiently if people are prepared beforehand. The following
table summarises the various open issues. I would like to issue a call for IEEE 802 participants to volunteer to lead discussions on each of the open issues, and ultimately to generate text for consideration in January 2017.
Please volunteer by sending me an e-mail.
A meta issue arises as to whether IEEE 802 should continue this process of “liaison ping pong”? Back in late 2015, 3GPP RAN leadership committed to not closing the Rel 13 specification until there was consensus from all stakeholders. It
was explicitly stated that IEEE 802 was one of those stakeholders. However, 3GPP RAN1 closed the Rel 13 specification before it had even responded to the initial comments from IEEE 802, and has ignored a number of IEEE 802 requests since then. Thoughts are
also sought on how to collaborate better with 3GPP RAN1 going forward.
Below is a summary of issues that arose from IEEE 802
liaison in July 2016 (the liaison was developed in IEEE 802.19 WG)
|
Issue |
IEEE 802 comment |
3GPP response |
Issue resolved? |
|
1-1 |
Requested that 3GPP RAN1 acknowledge transmission of energy to block channel should be avoided
|
Ignored the substance of IEEE 802 argument but stated that they may include a statement (not yet agreed) to suggest such transmissions should be “minimised” |
No |
|
1-2 |
Suggested transmission of blocking energy could be avoided by defining multiple sub-frame boundaries |
Stated that later versions of LAA may include this functionality |
? |
|
1-3 |
Requested 3GPP RAN1 confirm that HARQ operation is not related to comment 1-1 |
? |
? |
|
2 |
Requested 3GPP RAN1 impose additional constraints on DRS overheads |
Declined to impose constraints but asserted they were not needed in practice |
? |
|
3 |
Requests 3GPP RAN1 to consider an ED threshold based on a more realistic channel model |
Declined to make any changes based on assertion that current threshold was determined after consensus among 3GPP and IEEE 802 stakeholders. However, noted that the threshold will be evaluated by RAN4
|
No |
|
4 |
Requested that 3GPP RAN1 align LAA & 802.11 slots to preserve efficiency |
Rejected all aspects of the IEEE 802 request. Aside: in doing so, they actually made a good case to require detection and transmission of IEEE 802.11 preambles and NAVs |
No |
|
5 |
Suggested resolution of the multi-channel aggregation issue be postponed until coexistence tests can be run |
Agreed to wait for IEEE 802 input |
Yes |
|
6 |
Requested confirmation that it is mandatory to end transmissions at the shortest subframe boundary and further enhancements in LAA Rel 14. |
Ignored request in relation to accommodating partial sub-frames of one OFDM symbol duration |
? |
|
7 |
Requested minimum duration be defined in LAA Rel. 13 and a subframe of one OFDM symbol be defined in LAA Rel. 14 |
Ignored request in relation to Rel 13, but noted some related work is occurring in Rel 14 |
? |
|
8 |
Requested alignment of TxOP rules with those in ETSI BRAN EN 301 893 |
Rejected request on the basis there is no need to follow ETSI BRAN rules outside Europe
|
? |
|
9 |
Suggested resolution of the channel access contention window issue be postponed until further tests and simulations have been completed |
Responded to various elements of IEEE 802 response |
? |
|
10 |
Thanked 3GPP RAN1 for its clarification on CWp adjustment |
Confirmed IEEE 802 understanding |
Yes |
|
11 |
Noted IEEE 802’s comment on quanta of channel sense has been resolved |
Noted IEEE 802 response |
Yes |
|
12-1 |
Noted a remaining issue related to LAA Rel. 13’s backoff mechanism |
Asserted LAA “can” maintain slot alignment by monitoring the channel; also that any non-alignment is mitigated by checking channel for defer period |
? |
|
12-2 |
Noted an ambiguity in the LAA access mechanism |
Proposed a clarification that resolves the ambiguity |
? |
Below is a summary of issues that arose from IEEE 802 liaison in November 2016 (the liaison was developed in IEEE 802 PDED ad
hoc)
|
Issue |
IEEE 802 comment |
3GPP response |
Issue resolved? |
|
13 |
Requested support for
PD-based channel access in a future release of LAA specification |
Rejected request on basis that ED is a viable technology neutral solution which can ensure fair coexistence with IEEE 802.11 devices |
No |
|
14 |
Suggested future dialog on coexistence issues |
Accepted |
Yes |
Andrew Myles
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Andrew Myles |
Cisco Systems Limited |
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