1. The average number of call requests per unit time is also known as ________
a) Request rate
b) Load
c) Grade o Service
d) Traffic intensity
Explanation: Request rate is the average number of call requests per unit time. It is denoted by λ. Unit for request rate is second-1. It can also be defined as the ratio of traffic intensity of each user and the holding time
2. Traffic intensity offered by each user is the product of __________
a) Set up time and holding time
b) Call request rate and holding time
c) Load and holding time
d) Call request rate and set up time
Explanation: The traffic intensity offered by each user is equal to the call request rate multiplied by the holding time. Each user generates a traffic intensity A=λH Erlang. Here, H is the average duration of a call and λ is the average number of call requests per unit time for each user
3. AMPS cellular system is designed for a GOS of _____ blocking.
a) 10%
b) 50 %
c) 2%
d) 1%
Explanation: The AMPS (Advanced Mobile Phone System) cellular system is designed for a GOS of 2% blocking. This implies that the channel allocations for cell sites are designed so that 2 out of 100 calls will be blocked due to channel occupancy during the busiest hour
4. Blocked calls cleared formula is also known as _______ formula.
a) Erlang C
b) Erlang A
c) Erlang D
d) Erlang B
Explanation: Erlang B formula is also known as the blocked calls cleared formula. The Erlang B formula determines the probability that a call is blocked. And, it is a measure of the GOS for a trunked system which provides no queuing for blocked calls.
5. Blocked calls delayed formula is also known as _______
a) Erlang A
b) Erlang B
c) Erlang C
d) Erlang D
Explanation: Erlang C is also known as Blocked Calls Delayed. In this trunked system, a queue is provided to hold calls which are blocked. If a channel is not available immediately, the call request may be delayed until a channel becomes available.
6. Which of the following techniques do not help in expanding the capacity of cellular system?
a) Sectoring
b) Scattering
c) Splitting
d) Microcell zone concept
Explanation: As the demand for wireless service increases, the number of channels assigned to a call eventually becomes insufficient to support the required number of user. Techniques such as cell splitting, sectoring and coverage zone approaches are used in practice to expand the capacity of cellular system.
7. ________ uses directional antennas to control interference.
a) Sectoring
b) Cell splitting
c) Repeaters
d) Micro cell zone concept
Explanation: Sectoring uses directional antenna to further control the interference and frequency reuse of channels. By decreasing the cell radius R and keeping the co-channel reuse ratio D/R unchanged, cell splitting increases the number of channels per unit area
8. _______ allows an orderly growth of cellular system.
a) Sectoring
b) Scattering
c) Cell splitting
d) Micro cell zone technique
Explanation: Cell splitting allows an orderly growth of cellular system. By defining new cells which have a smaller radius than the original cells, capacity increases due to additional number of channels per unit area
9. Which of the following technology distributes the coverage of the cell and extends the cell boundary to hard-to-reach places?
a) Cell splitting
b) Scattering
c) Sectoring
d) Micro cell zone concept
Explanation: Micro cell zone concept distributes the coverage of the cell and extends the cell boundary to hard-to reach places. It is the solution for the problem of increased number of handoffs when sectoring which results in an increase of load on switching.
10. Which of the following increases the number of base stations in order to increase capacity?
a) Cell splitting
b) Sectoring
c) Repeaters
d) Micro cell zone concept
Explanation: Cell splitting increases the number of base stations in order to increase capacity. Whereas, sectoring and zone microcells rely on base station antenna placements to improve capacity by reducing co-channel interference.