LTE Emulator

LTE Emulator version 1.0 – technical report
The consecutive positions which have the minimum value of the defined distance dt_i are
combined in the following way: the counter (or probability) of the new group is the sum of the
two initial counters, and the numbers of bit errors/TTI (bit_erni) and bits/TTI (bitni) of the new
group are given by the weighted averages calculated according (10).
bit _ er
ni
bit _ er
ni
bit _ eri
⋅ contori
+ bit _ er
=
contor + contor
i−1
i−1
i−1
biti
⋅ contori
+ biti
−1
⋅ contor
=
contor + contor
i
i
⋅ contor
See fig. 5.9 for an example of the processing applied to data stored in the 3 tables presented in
fig. 5.8.
i i i j j j k k l l l m m
b d g a e h d e a e g c e
cnti-b cnti-d cnti-g cntj-a cntj-e cntj-h cntk-d cntk-e cntl-a cntl-e cntl-g cntm-c cntm-e
dt_m dt_m dt_m
(i⋅cnti-b+i⋅cnti-d)
/(cnt i-b+cnt i-d)
(b⋅cnt i-b+d⋅cnt i-d)
/(cnti-b+cnti-d)
i j (j⋅cntj-e+j⋅cntj-h)
/(cnt j-e+cnt j-h)
g a (e⋅cnt j-e+h⋅cnt j-h)
/(cntj-e+cntj-h)
no. errors/TTI - no. bits/TTI related to the decrease of these table lengths.
The operations described above are repeated until the lengths of the tables become smaller
than an imposed limit; e.g. the maximum length of the tables can be set to 128 or 256. Finally,
the positions in the counter table are replaced with the occurrence probabilities of the pairs of
random variables stored in the two other tables, i.e. the pdf functions of these pairs, and after this
operation the pdf function is replaced by the cdf function.
The simulation program generates as output data two files:
o a text file (stat_file.txt), which stores the data of the initial tables, i.e. the distances
between consecutive errors, and the counters of these distances (see fig. 5.5.), and the
data of the matrix with the numbers of errors/TTI, numbers of bits/TTI and the counters
of these groups of data (see fig 5.7.);
o a file stream (stat_file.sta), which contains the representation of the final cdf functions
associated to the distances between errors and to the pairs (no. errors/TTI; no. bits/TTI),
see figures 5.6. and 5.9.
i−1
i−1
k k l l (l⋅cntl-g+m⋅cntm-c)
/(cnt l-g+cnt m-g)
d e a e (g⋅cnt l-g+c⋅cnt m-c)
/(cntl-g+cntm-g)
cnti-b+cnti-d cnti-g cntj-a cntj-e+cntj-h cntk-d cntk-e cntl-a cntl-e cntl-g+cntm-c cntm-e
Fig. 5.9. Processing of tables which describe the bi-dimensional random variable.
m
e
(10)
bits/TTI
bit errors
/TTI
counter
bits/TTI
bit errors
/TTI
counter
29