Reed-Solomon), DVB-T2 coding rate may be much higher and the overall
throughputof the channel increases substantially.
4.
STUDYing the performance indicators when using the DVB-T2 standard
4.1.
Features of the definition of performance indicators in multiservice duplex
system.
Data transmission quality can be determined in terms of throughput,
productivity and range of the transmitted information. As it follows from the well
known formula for the throughput throughput C using predetermined manipulation
index M [7, 14]:
í µí°¶=í µí±‰âˆ™[í µí±™í µí±œí µí±”í µí±€âˆ’í µí±†í µí°¸í µí±…âˆ™í µí±™í µí±œí µí±”
í µí±†í µí°¸í µí±…
í µí±€âˆ’1
−(1âˆ’í µí±†í µí°¸í µí±…)âˆ™í µí±™í µí±œí µí±”(1âˆ’í µí±†í µí°¸í µí±…)], (1)
where M – number of bits per symbol for a selected modulation type.
On the one hand, the throughput increases with symbol rate in the channel V; on
the other hand, its growth is limited by the increase in BER and SER to the acceleration
V. Simultaneously, the error probability is higher when the larger multiplicity
manipulation M used.
Thus, if SER values of multipoint signal are known, then the throughput can be
identified at a predetermined manipulation.
Telecommunication network productivity depends on many factors such as the
data transmission medium, the radio waves frequency, transceiver devices placement
and their configuration. It is extremely important to understand what kind of
improvements have been implemented in this standard, what they do, when using the
DVB-T2 standard devices. Network performance represents such a characteristic of
the system, which determines the actual allowable transmission rate information in the
channel. Productivity is calculated as follows:
í µí±…
1
=í µí±‰âˆ™[1+(1âˆ’í µí°µí µí°¸í µí±…)âˆ™í µí±™í µí±œí µí±”
2
(1âˆ’í µí°µí µí°¸í µí±…)+í µí°µí µí°¸í µí±…âˆ™í µí±™í µí±œí µí±”
2
í µí°µí µí°¸í µí±…], (2)
This parameter is limited and depends on BER. This productivity is a
performance of a single channel, and the total consists of N productivities as:
í µí±…
í µí± í µí±¢í µí±š
=í µí±…
1
í µí±™í µí±œí µí±”
2
í µí±€,
(3)
Thus, to accurately determine the likelihood of SER, need evaluate the throughput
of the communication channel; and to accurately determine BER, need evaluate the
productivity. These parameters are very closely related to the distance of information
transmission.
Technical literature provides different equations to calculate SER and BER.
Among them – the results of vector-phase method (VPM) [15], and results from J.
Proakis [16]. In this work, the analysis performed according to manipulation specified
in DVB-T2 standard, namely: QPSK, QAM-16, QAM-64 and QAM-256. These
calculations are performed by the VPM and using J. Proakis formulas.
The VPM is used to obtain accurate results. VPM intends to determine the
probability of resultant signal and noise aggregated vector to belong to some certain
- 581 -