rwirelesscom (version 1.4.3)

f64qammod: 64-QAM Modulator

Description

Receives a vector of bits (1's and 0's). The received vector is mapped to an in-phase (real) and quadrature (imaginary) 64-QAM (6 bit) symbol according to a Binary Reflective Gray Code (BRGC, see reference). In-phase and quadrature constellation points take on values -7, -5, -3, -1, +1, +3, +5, +7, respectively, corresponding to a symbol energy Es = 42. Mapping of bits to 64-QAM constellation points is illustrated in the following constellation.

-7+7i	-5+7i	+3+7i	-1+7i	+1+7i	+3+7i	+5+7i
+7+7i	(100000)	(100001)	(100011)	(100010)	(100110)	(100111)
(100101)	(100100)
	-7+5i	-5+5i	+3+5i	-1+5i	+1+5i	+3+5i
+5+5i	+7+5i	(101000)	(101001)	(101011)	(101010)	(101110)
(101111)	(101101)	(101100)
		-7+3i	-5+3i	+3+3i	-1+3i	+1+3i
+3+3i	+5+3i	+7+3i	(111000)	(111001)	(111011)	(111010)
(111110)	(111111)	(111101)	(111100)
			-7+1i	-5+1i	+3+1i	-1+1i
+1+1i	+3+1i	+5+1i	+7+1i	(110000)	(110001)	(110011)
(110010)	(110110)	(110111)	(110101)	(110100)
				-7-1i	-5-1i	+3-1i
-1-1i	+1-1i	+3-1i	+5-1i	+7-1i	(010000)	(010001)
(010011)	(010010)	(010110)	(010111)	(010101)	(010100)
					-7-3i	-5-3i
+3-3i	-1-3i	+1-3i	+3-3i	+5-3i	+7-3i	(011000)
(011001)	(011011)	(011010)	(011110)	(011111)	(011101)	(011100)
						-7-5i
-5-5i	+3-5i	-1-5i	+1-5i	+3-5i	+5-5i	+7-5i
(001000)	(001001)	(001011)	(001010)	(001110)	(001111)	(001101)
(001100)
-7-7i	-5-7i	+3-7i	-1-7i	+1-7i	+3-7i	+5-7i
+7-7i	-7+7i	-5+7i	+3+7i	-1+7i	+1+7i	+3+7i

Reference: E. Agrell, J Lassing, E. Strom, and T. Ottosson, Gray Coding for Multilevel Constellations In Gaussian Noise, IEEE Transactions on Communications, Vol. 53, No. 1, January 2007

Usage

f64qammod(bits, Ns = 1, p = 1)

Arguments

bits

- received vector of bits (0's and 1's).

Ns

- N samples per symbol (default, Ns = 1)

p

- a vector defining the pulse shape of the transmitted waveform (default, p = 1)

Value

Returns a complex vector of 64-QAM symbols. If Ns > 1 then the returned signal is shaped with pulse shape, p.

See Also

Other rwirelesscom functions: eyediagram; f16pskdemod; f16pskmod; f16qamdemod; f16qammod; f64qamdemod; f8pskdemod; f8pskmod; fNo; fbpskdemod; fbpskmod; fqpskdemod; iqdensityplot; iqscatterplot; stemplot

Examples

M=64
Es=42
Eb = Es/log2(M)
Nsymbols=1000
Nbits=log2(M)*Nsymbols
bits <- sample(0:1,Nbits, replace=TRUE)
s <- f64qammod(bits)