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multiple users, likely generates a lot more daytime traffic than a simple residential service
used for Web browsing and email.
In summary, the network design engineer must be aware of the intended use of the system —
the customer profile, tariff rates, and committed grades of service — since these factors all
influence the traffic demand on the system.
5.3
Multi-CAP RF Network Design Considerations
One of the differentiating features of the LMS4000 900MHz radio system is its ability to
support multi-CAP networks. The design of multi-CAP networks is significantly more complex
than the design of single-CCU or single-CAP systems. WaveRider highly recommends the use
of a qualified RF engineering firm, such as the WaveRider Professional Services Group, to
carry out multi-CAP system design. If you are confident that you have the required skill set
available in house, you can carry out this design yourself.
5.3.1 Multi-CAP Network Design Process
The process for designing a multi-CAP network can be summarized as follows:
1. Conduct a preliminary site survey and selection.
2. Apply a frequency grid to the sites that you have selected.
3. Determine the site-to-site signal levels by
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•
•
•
4. Using the C/I information presented in
frequency plan and channel assignment.
5. Perform and apply antenna down-tilt calculations.
6. Assess the impact of known in-band and out-of-band interferers.
7. Verify and iterate the design as many times as necessary.
This chapter does not provide detailed instructions on how to carry out each of the above
tasks as it is beyond the scope of the document. It does, however, provide you with the
LMS4000-specific information that you or your RF engineering firm need to be able to carry
out the above steps.
5.3.2 Frequency Selection — Standard Frequency Set
LMS4000 900 MHz equipment (CCUs and EUMs) can operate on all channels from 905 to
925 MHz, in increments of 0.2 MHz (refer to
APCD-LM043-4.0
Determining site-to-site distances,
Calculating site-to-site propagation loss,
Normalizing the signal levels at each site, and
Factoring in the antenna isolation.
C/I Requirements
on page 68, formulate a
Table 6 on page 29
for channelization
5 Radio Network Planning
67
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