mesh network using TI cc1100 design issue

[fireball003]

Hi,
I am an embedded system engineer, but almost newbie in wireless communication. I will have to design a custom protocol for sets of speedy mobile devices which will communicate reliably without connection (I don't know if this term is right,please correct me), unlike to wifi which need to connect to each other first. This is due to the short time for data transfer.

My idea is to use any of the 300-348, 391-464 Mhz bands and to design a custom protocol for this. Requirements are-
# Connectionless communication (as opposed to bluetooth or wifi).
# Observe all the channels for data.
# send data to/receive data from up to 32 devices at the same time.
# No collision (like zigbee, watch which channel is free and then use that).
# There will be at least 1 and upto 4 emergency channels which will be always open and data can be sent using those channels anytime without waiting for availability.

Is there any contradiction or feasibility related issue in the requirements?


I was looking at TI cc11xx series for this project. Unfortunately I couldn't find any evaluation/development board which supports whole 391-464 MHz band (as the devices need to monitor all the channels for data). Any suggestion?

Does the support for the spectrum for cc11xx series depend on the antenna? if so, will you please suggest an antenna that supports the whole band?

Please comment or suggest me on anything related to this project based on your experience and ideas. I really appreciate your help.

Thanks in advance.

 

[Mazz]

Seeing your post just now.

One limitation is for sure the antenna. In antennas the relative bandwidth is an important parameter. You have to make a custom design to obtain large bandwidth.

Regulation in your country is another limitation: in the Sub-1 GHz there isn't large BW available. Did you check it?

How many channels do you need? and data rate?

If the data rate is low, you can look at narrowband transceivers. In this applications you can put a large number of channels in a small bandwidth, because each channel uses a small band.

I hope it can help.

Mazz