Receivers and symbol decoders thereof
View Patent ↗A receiver capable of decoding a symbol based on information on a previous symbol, the symbol and a next symbol in a Gaussian frequency shift keying (GFSK) communication system is provided. The receiver includes a discriminator to generate a symbol for each bit in a bit sequence, a first lookup table (LUT) to store a number of bit patterns and mapping patterns, wherein each of the bit patterns is in the form of a set of consecutive bits in the bit sequence and corresponds to a respective one of the mapping patterns, and wherein each of the mapping patterns includes a set of entries and each of the entries results from an operation of attribute values at a sample time in the waveform of a symbol, a calculator to receive a set of consecutive symbols from the discriminator and calculate a distance value between the set of consecutive symbols and each of the mapping patterns, and a comparator to identify one of the mapping patterns with a minimum distance value by comparing among the distance values from the calculator.
1. A receiver capable of decoding a symbol based on information on a previous symbol, the symbol and a next symbol in a Gaussian frequency shift keying (GFSK) communication system, the receiver comprising:
a discriminator to generate a symbol for each bit in a bit sequence;
a first lookup table (LUT) to store a number of bit patterns and mapping patterns, wherein each of the bit patterns is in the form of a set of consecutive bits in the bit sequence and corresponds to a respective one of the mapping patterns, and wherein each of the mapping patterns includes a set of entries and each of the entries results from an operation of attribute values at a sample time in the waveform of a symbol;
a calculator to receive a set of consecutive symbols from the discriminator and calculate a distance value between the set of consecutive symbols and each of the mapping patterns; and
a comparator to identify one of the mapping patterns with a minimum distance value by comparing among the distance values from the calculator.
2. The receiver of claim 1 , wherein the first LUT stores a number of pattern indexes each corresponding to a respective one of the bit patterns.
3. The receiver of claim 2 , wherein the first LUT outputs one of the bit patterns corresponding to the pattern index that in turn corresponds to one of the mapping patterns.
4. The receiver of claim 3 further comprising a memory module to output a middle bit of the one of the bit patterns in response to the pattern index.
5. The receiver of claim 1 , wherein the attribute values include values “a”, “d” and “c”:
a
=
h
4
T
s
(
f
4
-
2
f
0
)
,
d
=
hf
4
2
T
s
,
and
c
=
h
2
T
s
(
f
4
+
2
f
0
)
,
where h represents a modulation index, T s represents a symbol time, f 4 represents a sampling point where the impulse response of a symbol is exactly sampled, and f 0 represents a sampling point where the impulse response of a symbol is the weakest.
6. The receiver of claim 1 , wherein the calculator is configured to calculate the Euclidean distance between the set of consecutive symbols and each of the mapping patterns.
7. The receiver of claim 1 , wherein each of the bit patterns includes a set of “n” consecutive bits, n being one of 3, 5 and 7.
8. The receiver of claim 1 further comprising a second LUT to store a number of bit patterns, wherein each of the bit patterns includes a set of consecutive bits with the leading two bits predetermined.
9. The receiver of claim 8 , wherein the second LUT stores a number of pattern indexes each corresponding to a respective one of the bit patterns in the second LUT.
10. The receiver of claim 1 further comprising a third LUT to store a number of bit patterns for decoding the first bit and the last bit in the bit sequence, wherein each of the bit patterns includes a set of three consecutive bits.
11. The receiver of claim 1 further comprising a fourth LUT to store a number of bit patterns for decoding the second bit and the second to last bit in the bit sequence, wherein each of the bit patterns includes a set of four consecutive bits.
12. A receiver capable of decoding a symbol based on information on a previous symbol, the symbol and a next symbol in a Gaussian frequency shift keying (GFSK) communication system, the receiver comprising:
a discriminator to generate a symbol for each bit in a bit sequence;
a first lookup table (LUT) to store a number of bit patterns and mapping patterns, wherein each of the bit patterns is in the form of a set of (2n+1) consecutive bits with the leading “n” bits of each of the bit patterns being predetermined, and corresponds to a respective one of the mapping patterns, “n” being an integer equal to or greater than 2, and wherein each of the mapping patterns includes a set of entries and each of the entries results from an operation of attribute values at a sample time in the waveform of a symbol;
a calculator to receive a set of consecutive symbols from the discriminator and calculate a distance value between the set of consecutive symbols and each of the mapping patterns; and
a comparator to identify one of the mapping patterns with a minimum distance value by comparing among the distance values from the calculator.
13. The receiver of claim 12 , wherein the first LUT stores a number of pattern indexes each corresponding to a respective one of the bit patterns.
14. The receiver of claim 13 , wherein the first LUT outputs one of the bit patterns corresponding to the pattern index that in turn corresponds to one of the mapping patterns.
15. The receiver of claim 14 further comprising a memory module to output a middle bit of the one of the bit patterns in response to the pattern index.
16. The receiver of claim 12 , wherein the attribute values include values “a”, “d” and “c”:
a
=
h
4
T
s
(
f
4
-
2
f
0
)
,
d
=
hf
4
2
T
s
,
and
c
=
h
2
T
s
(
f
4
+
2
f
0
)
,
where h represents a modulation index, T s represents a symbol time, f 4 represents a sampling point where the impulse response of a symbol is exactly sampled, and f 0 represents a sampling point where the impulse response of a symbol is the weakest.
17. The receiver of claim 12 , wherein the calculator is configured to calculate the Euclidean distance between the set of consecutive symbols and each of the mapping patterns.
18. The receiver of claim 12 further comprising a second LUT to store a number of bit patterns for decoding the first bit and the last bit in the bit sequence, wherein each of the bit patterns includes a set of three consecutive bits.
19. The receiver of claim 12 further comprising a third LUT to store a number of bit patterns for decoding the second bit and the second to last bit in the bit sequence, wherein each of the bit patterns includes a set of four consecutive bits.