Recent Question/Assignment

Telecommunications & Network Management COMT6001
Assignment 1
To be handed in at the lecture on the 15th September, 2017
Q1
a)
In the Telecommunications Act, describe what is meant by the term an Unbundled Local Loop (ULL)?
In 1999 the ACCC made ULL a declared service – what is the meaning of a “declared service” under the Telecommunications Act and why is it important in promoting competition amongst Telecommunications Carriers?
b)
Name the two major Service Obligations and one Service Guarantee required of registered Telecommunications Carriers under the Telecommunications Act that implements the Social Policy of the Telecommunications Act and briefly state the purpose of each?
c)
Nominate which Australian Government Institution / Agency manage the following parts of the current Telecom 1997 Act and briefly describe their function with regard to the Australian Telecommunications market.
1) The Telecommunications Act
2) Telecom Market Entry
3) Price and Competition
4) Customer Complaints about telecommunications services
25%
Q2
A microwave radio site has two 6.7 GHz, 298 Mbps microwave radio systems radiating from the site. The antenna type, bearing and the path length of each of the radio bearers are listed in this table. The Wanted to Interfering Unwanted ratio (W/U) required for co-channel operation
is given in the attached 6.7 GHz Band Plan RALI and the antenna Radiation Pattern Envelopes are also attached.
Radio System Antenna Type Bearing Path Length
A HPX12-65 0° N 50 Km
B HP8-65 30° N 25 Km
a) Calculate the Received Signal Level for each of the two radio systems assuming that the Transmitter Power is 0.5 W, the RF cable losses are 3 dB for each RF feeder and the RF circulator/fixed losses for each antenna system is 3 dB.
b) Calculate if there is sufficient W/U to allow each of the bearers to transmit on channel 4 (6720 MHz) without interfering with the receivers of the other radio bearers (you can allocate either polarisation for each bearer to achieve the required antenna discrimination). Draw a diagram of the possible interfering paths and show how you calculated the Wanted signal to Unwanted interfering signal ratio for each of the possible interfering paths.
What frequency and polarisations would be required in this configuration?
c) If the bearing of the radio system B is increased to 80° N calculate if both radio systems can now operate on channel 1?
25%
Q3 Three Local Exchanges connect to the Primary Exchange via direct first choice routes with second choice routes provided via a Transit Exchange (see diagram below). The first choice Grade of Service (GoS) is set at 10% and the second choice GoS is set at 0.5%. For the amount of TCBH traffic shown in the diagram for each exchange:
a) Calculate the number of circuits required on each of the first choice routes to meet the 10% GoS.
b) Calculate the amount of traffic offered to each of the second choice routes and dimension the number of circuits on these routes (including the Transit to Primary exchange link) for the 0.5% GoS.
c) If the Primary to Transit Exchange link fails for the busy hour, how many calls would be lost if the average call duration is 2.5 minutes?
d) If the first choice route for Exchange 1 fails, how much traffic (in Erlangs) would be able to reach the Transit Exchange if the GoS for the duration of the outage is set at 10%?
e) After six months of operation a TCBH traffic measurement is undertaken on the Transit Exchange to Primary Exchange route with the result of 14 Erlangs of TCBH traffic. What is the approximate GoS indicated by this traffic measurement, explain what that GoS indicates has occurred and what action, if any, should be taken by the network planner?
25%
Q4 A Company has offices in Perth and Sydney generating the following levels of Time Consistent Busy Hour (TCBH) Telephone Traffic:
PERTH SYDNEY
Incoming PSTN Customer Calls 300 calls @ 3min average 600 minutes of calls
Incoming PSTN Office Calls 100 calls @ 3.5min average 240 minutes of calls
Outgoing PSTN Calls 200 calls @ 2.5min average 480 minutes of calls
Inter-Office Calls 10E
a) Dimension the minimum number of exchange lines from the Carrier Exchanges that need to be connected to the Perth and Sydney PABXs to carry the measured Incoming & Outgoing traffic for a Grade of Service of 0.5%.
b) Dimension the minimum number of voice tie lines between Perth and Sydney required to carry the measured inter-PABX traffic for a Grade of Service of 0.5%, 1% and 10%.
c) Draw a diagram of the above company network showing the number of exchange lines and inter-office tie lines connecting to the Perth and Sydney offices as dimensioned in parts (a) & (b) above?
d) Assuming that all customer calls to the Perth & Sydney offices are routed by the Telephone Carrier’s network to the Perth office, re-dimension the PSTN exchange lines and voice tie lines so that the Sydney incoming customer call traffic can be answered in Sydney via the inter-office voice tie lines (Note: Sydney Incoming PSTN Office Calls & Outgoing PSTN calls continue to be connected via Sydney PSTN lines)? In this configuration what Grade of Service have you selected for the PSTN and voice tie line routes and explain why you have selected this GoS.
25%
THE 6.7 GHz BAND (6425 - 7110 MHz)
RF CHANNEL ARRANGEMENTS
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ASSIGNMENT INSTRUCTIONS
This band is designated for use by digital high capacity fixed point-to-point links.
Typical Use : 40 MHz channels - 140 Mbit/s data
: 80 MHz channels - 298 Mbit/s data
Assignment Priority : 80 MHz channels - from highest channel downwards
Minimum Path Length : 20 km
Antenna Requirements : refer to Appendix 11
Note:
1. Proposed links need to be coordinated with licensed earth stations operating in this band.
2. The channel raster known previously as the interleaved raster has been removed. No new assignments are to be made.
3. Potential for interference to and from adjacent 6 GHz band fixed services.
Reference
1. Rec. ITU-R F.384-5, “Radio-frequency channel arrangements for medium and high capacity analogue or high capacity digital radio-relay systems operating in the upper 6 GHz band”.
[6.7 GHz - Page 1 of 3]
FX 3 Appendix 1 - RF Channel Arrangements and Assignment Instructions October 2014
THE 6.7 GHz BAND (6425 - 7110 MHz)
PROTECTION RATIOS
1. Protection ratios required between digital systems.
Frequency Offset
(MHz)
PROTECTION RATIO (dB)
Interferer Tx o Victim Rx
40 MHz p
40 MHz 40 MHz p
80 MHz 80 MHz p
40 MHz 80 MHz p
80 MHz
0 60 69
20 68 56
40 30
60 50 35
80 0 46
100 15 12
140 8 4
160 15
2. Protection ratios required between digital systems in the adjacent 6 GHz band.
Frequency Offset
(MHz)
PROTECTION RATIO (dB)
Digital Interferer Tx o Digital Victim Rx
40 MHz p
29.65 MHz 40 MHz p
59.3 MHz 80 MHz p
29.65 MHz 80 MHz p
59.3 MHz
55.21 12
70.035 20
75.21 15
84.86 1.5
90.035 24
104.86 10
Note:
1. Protection ratios for digital systems are based on a 50 km path length and PL (Percentage of time that the average refractivity gradient in the lowest 100 m of the atmosphere is less than or equal to -100 N units/km) of 20. For other path lengths and PL values refer to the protection ratio correction factors graph on the following page.
[6.7 GHz - Page 2 of 3]
FX 3 Appendix 1 - RF Channel Arrangements and Assignment Instructions October 2014

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