Provisioning both wireless voice and wireless location services

Unanswered Question

Customer needs both wireless location services and also wireless voice. My thought is to use 802.11a for voice with the 7921G and 802.11b for location services. Since location services requires the highest AP density, it would seem that an 802.11b survey for location services would result in the resulting AP grid likely being able to support voice at 802.11a. Has anyone had experience with this? What are some suggestions for spectrum use and for performing a survey when both wireless voice and wireless location services are required?

I have this problem too.
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diro Thu, 04/05/2007 - 06:16

Hi,

You should survey for voice on the a radio (a has less coverage then b/g). And then add additional accespoints so that you can do triangulation for location.

It's a good idea to use the 802.11a radio for phones because fot the monent ther is less interference.

Dimitri

richcortes Tue, 09/25/2007 - 08:05

Has anyone seen any design requirements for voice over 802.11a? I keep seeing -67db and that is the typical number for voice @ 11Mb in the 802.11bg space. Is the same true for 802.11a, -67db at 54Mb? Any help would be great. I have 4 buildings that are going to undergo a survey starting in 2 weeks. Thanks.

syeali Sun, 04/08/2007 - 13:49

Hi,

You cannot use 802.11a with 7921G since, as the name suggests, 7921G has G-radio that works with 802.11b/g in the 2.4GHz space.

syeali Sun, 04/08/2007 - 21:22

Hi, my bad. Indeed you can use the 7921G in the 802.11a space. Please ignore my earlier comment.

migilles Wed, 09/26/2007 - 18:38

G stands for Global not 802.11 mode. :)

So for the 7921 signal requirements, yes -67 dBm is what you want to design for. This will give adequate signal to the phone as well as allowing for other channels to be discovered for potential roaming.

See the 7921G Deployment Guide, which includes receiver sensitivity values for each rate. However, will need to add some padding there as you don't want to be on the edge otherwise will be packet loss.

http://www.cisco.com/univercd/cc/td/doc/product/voice/c_ipphon/english/wip7921/7921dply.pdf.

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