LAA still on track for March 2016 R13 deadline, although 3GPP concedes more to do on coexistence

Over 200 participants attended the 3GPP's workshop on Licensed-Assisted Access in Beijing on Saturday. Here's what was decided.

The 3GPP still expects to freeze the specification of downlink Licensed-Assisted Access (LAA) LTE within R13 in March 2016, and has stated that “things are going in the right direction” for the technology. However, it also conceded that there are still a “few remaining technical details that will have to be discussed in the coming months”, following the submission of  further evidence and technical analyses by IEEE and the Wi-Fi Alliance to a workshop meeting held in Beijing on 29 August.

During the meeting, attended by 210 participants, 3GPP moved to reassure the Wi-Fi co-respondents that they would have sufficient time to study and respond to specifications, specifically those relating to co-existence. The 3GPP said that although all elements that would affect backwards compatibility would need to be frozen by March 2016, there would still be the opportunity to change the values of some parameters “if deemed necessary”. It also said it believed there is alerady good co-operation from a detailed technical perspective.

As TMN reported prior to the event, the Wi-Fi bodies also called for open platform co-existence testing to be established, and 3GPP said that it would “start to interact on this in the coming months”, pointing out that “there is a need to increase understanding on how this will be achieved”. The IEEE told the meeting it would like to see collaboration established between IEEE 802 and RAN 5, and 3GPP said it was “totally open to such interaction”.

The IEEE’s submission, given by Cisco’s Andrew Myles generated a good deal of comment. Most of these centred around how IEEE could be included in collaboration efforts as 3GPP continued its discussions, without everything slowing down and deadlines being missed.

IEEE said that it is important to, “Get people in the same room (even virtual room) – make sure 3GPP treats the inputs from IEEE seriously”. Others pointed out that collaboration is an ongoing process.  Samsung said it was very important that the March 2016 deadline for LAA is not touched, and the 3GPP, having said that full Change Requests (CRs) could be made after March, June, September 2016, giving the opportunity for further tweaks to co-existence parameters, also said it would set a deadline of December 2015 for baseline Change Requests to be set out and ready for comment.

The upshot, then, is that downlink LAA is still on course to be frozen into 3GPP R13 in March 2016, although some of the trickier issues in the detail remain up for grabs. The Wi-Fi bodies will hope to use this time to have their input listened to and included. They will also hope to be equal partners in developing performance requirements for coexistence testing.

The Beijing meeting was set up to assuage fears in what might be termed the Wi-Fi “camp” that LAA was going to be defined solely by the 3GPP, to the detriment of the Wi-Fi ecosystem and of users of Wi-Fi. 3GPP has been keen to point out that it had only adopted LAA as a technical study item until June this year, when it determined that it would move the project  to normative phase with the specification of LAA downlink operation in Rel-13. It has looked to reassure the Wi-Fi bodies that they can provide input into LAA specification, with the Biejing workshop a key element of that reassurance.

The meeting ended with the following conclusions:

LAA/LBT design

RAN1 should send out the agreed LAA CRs in Q4 2015

Further comments from IEEE  and WFA are welcome
 – Things seem to be going in the right direction but there may be some outstanding issues to discuss based on further evidence and technical analysis.

It was clarified that comments and changes will be possible in the coming months
 – Release freeze is not a hard deadline for changes (it only impacts the possibility to do ASN.1 non backward compattible changes; very unlikely that will prevent changing values of some parameters if deemed necessary)
 – As per normal process, 3GPP does quartely updates of the specs with Change Requests (CR)

Coexistence testing

Discussion is about to start in 3GPP

Release 13 LAA will focus on DL only operations

3GPP RAN4 will develop coexistence / performances requirements and tests for LAA

Inputs from WFA and IEEE will be welcome in this phase as well

WFA has started coexistence testing effort covering WIFI to WIFI and WIFI to LAA coexistence and will keep 3GPP informed about the effort

 

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