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Dear all,
Thanks for Chiwoo’s analysis and Yi-Ting’s information.
Chiwoo’s analysis shows that the current 16m feedback channel design allows at most 12032 devices operating in active mode. Can we agree firstly no matter which number we decide to apply shall not exceed that number?
I agree Hyunjeong and Jaesun’s opinions that most of the M2M devices will stay in idle mode rather than in active mode. In this case we don’t really need to make a long device ID. In my opinion, having another ID which is larger than 12-bit STID will impact the 16m A-MAP CRC masking scheme, and induce backward support problem.
It’s discussable whether a 12-bit ID is enough or not to support all active 16m and M2M devices. In case it is not enough, we can also let multiple M2M devices share the same ID to resolve the problem.
Thank you for supplying this information, however, as the document indicates both for Taipei and for London, the deployments utilize a local concentrator with an average of 25 meters per concentrator. This is also consistent with the architecture promulgated by the US utility companies (who refer to the concentrator as a Data Aggregation Point , DAP, and assume up to 1000 meters per DAP). So, as the R2 contribution indicates, the calculations need to be based on the number of concentrators (approximately 1000 – 1500 per 1 km cell) and their traffic load, not the number of individual meters.
From: 林奕廷 (Lin, Yi-Ting) [mailto:eating@NMI.III.ORG.TW]
Sent: Thursday, February 10, 2011 11:38 PM
To: STDS-802-16@LISTSERV.IEEE.ORG
Subject: Re: [STDS-802-16] [802.16p][DEV-RG] - Email Discussion on M2M device identification
Dear all,
Thanks for Chiwoo's analyses. We agree that, with current 16m feedback channel design, the maximum number of devices would be 12032.
We would like to share our experiences on smart meters in Taipei. Please refer to the file <http://www.3gpp.org/ftp/tsg_ran/WG2_RL2/TSGR2_70/Docs/R2-103269.zip> for reference. For a cell of 1 km radius, the number of smart meters could be more than 30000. In practice it is not likely all smart meters attach to the network at the same time. But, considering various M2M applications would run simultaneously in a cell, we think the value of 30000 is reasonable to be the baseline number of supported devices.
Best Regards,
Yi-Ting
From: Lim Chiwoo
Sent: Friday, February 11, 2011 10:08 AM
Subject: Re: [STDS-802-16] [802.16p][DEV-RG] - Email Discussion on M2M device identification
Dear 16p members,
As Kaushik pointed, we couldn’t agree on how many devices we need to support or how many devices we can currently support.
According to addressing issue, it’s required to determine this first.
I want to show my calculations about current feedback capacities of 16m and 16e.
I think that the size of STID doesn’t need to largely exceed the capacity of feedback channel because operation is not guaranteed if there is no relevant feedback.
The results show that the number of supportable user based on feedback channel are 7168/12032/200 in cases of 16m(10MHz)/16m(20MHz)/16e(10MHz), respectively.
I think that we can consider these results when we determine the number of devices to be supported in M2M.
Please let me know your opinion.
Please see following calculations.
Basic conditions
- DL:UL = 5:3
- One feedback channel makes 6 HARQ feedback channels.
- Maximum number of LRUs for feedback channel : 16 (4 bits indication)
- Maximum number of HARQ feedback channel is 30/60 for 10/20MHz, respectively.
- Let’s consider maximum HARQ feedback channel.
- The report period of fast feedback channel is up to 128 frames (=640ms, 3 bits indication)
-
<10MHz case, 16m>
There is a restriction of number of feedback channel. The MAX number is 27. (per one subframe)
5 feedback channels are used for HARQ feedback channels. (per one DL subframe (one HARQ feedback region))
There are 81 (= 27 * 3) feedback channels per one frame.
25 (=5*5) feedback channels are used for HARQ feedback channel.
That is, there are 56 fast feedback channels in a frame.
When we consider the report period as 8/32/128 frames, the number of supportable user are 448/1792/7168.
<20MHz case, 16m>
There are 48 feedback channels. (per one subframe)
10 feedback channels are used for HARQ feedback channels. (per one DL subframe (one HARQ feedback region))
There are 144 (= 48 * 3) feedback channels per one frame.
50 (=10*5) feedback channels are used for HARQ feedback channel.
That is, there are 94 fast feedback channels in a frame.
When we consider the report period as 8/32/128 frames, the number of supportable user are 752/3008/12032.
<10MHz case, 16e>
In 16e, the report period of CQICH channel is up to 8 frames (= 40ms, 2bits indication)
There are 35 subchannels per one frame in 10MHz.
6 subchannel shall be used as ranging channel.
Therefore, if we assume 25 subchannels for CQICH and 4 subchannels for ACK/NAK, the number of supportable user is just 200.
BR,
Chiwoo
From: Kaushik Josiam [mailto:kjosiam@STA.SAMSUNG.COM]
Sent: Thursday, February 10, 2011 5:28 AM
To: STDS-802-16@LISTSERV.IEEE.ORG
Subject: [STDS-802-16] [802.16p][DEV-RG] - Email Discussion on M2M device identification
Dear 16p members
In the DEV RG conference call today, we wanted to hear the member’s view on how many devices we need to support in 802.16p systems. We can increase the addressing space to support a large number of users, but in the conference call, we couldn’t agree on how many devices we need to support or how many devices we can currently support.
Related to this issue, do we need to define a new M2M specific IDs for M2M devices?
If you have any thoughts or proposals on the issue, please share them as a reply to this thread.
We thank you for your cooperation.
Regards
Kaushik & Ming-Hung
DEV RG Chairs