A Jointly Optimized Variable M-QAM and Power Allocation Scheme for Image Transmission

Table 1

Distribution of the modulation levels for different power optimized schemes and their gains.

	MSB							LSB	Average spectral efficiency	BW efficiency gain%	Gain at 𝐸𝑏/𝑁0=0dB	Gain at 𝐸𝑏/𝑁0=4dB	Gain at 𝐸𝑏/𝑁0=8dB	Gain at 𝐸𝑏/𝑁0=12dB	Gain at 𝐸𝑏/𝑁0=16dB
Combination number	𝑚7	𝑚6	𝑚5	𝑚4	𝑚3	𝑚2	𝑚1	𝑚0
1	16	16	16	16	16	16	16	16	4	0	4.97	7.84	11.11	12.79	11.33
2	64	16	16	16	16	16	16	4	4	0	7.55	10.83	14.47	15.07	6.75
3	64	16	16	16	16	16	16	16	4.25	6.25	4.98	7.87	11.15	11.63	2.93
4	64	64	16	16	16	16	4	4	4	0	9.50	13.45	17.21	15.73	4.68
5	64	64	16	16	16	16	16	4	4.25	6.25	7.59	10.90	14.73	12.89	−0.54
6	64	64	16	16	16	16	16	16	4.5	12.5	5.01	7.93	11.12	9.9	−3.79
7	64	64	64	16	16	4	4	4	4	0	10.71	15.58	18.17	14.81	1.07
8	64	64	64	16	16	16	4	4	4.25	6.25	9.59	13.48	16.05	12.51	−2.03
9	64	64	64	16	16	16	16	4	4.5	12.5	7.66	10.92	13.66	10.15	−5.25
10	64	64	64	16	16	16	16	16	4.75	18.75	5.06	8.01	10.84	7.72	−9.38
11	64	64	64	64	4	4	4	4	4	0	11.13	16.38	17.43	12.78	−3.65
12	64	64	64	64	16	4	4	4	4.25	6.25	10.82	15.05	15.99	11.16	−6.59
13	64	64	64	64	16	16	4	4	4.5	12.5	9.68	13.23	14.24	9.14	−8.65
14	64	64	64	64	16	16	16	4	4.75	18.75	7.74	10.87	12.20	7.31	−11.69
15	64	64	64	64	16	16	16	16	5	25	5.15	8.03	9.75	5.18	−14.22
16	64	64	64	64	64	4	4	4	4.5	12.5	10.86	13.47	13.28	7.373	−12.54
17	64	64	64	64	64	16	4	4	4.75	18.75	9.73	12.03	11.81	5.87	−14.41
18	64	64	64	64	64	16	16	4	5	25	7.82	10.08	10.04	4.20	−16.93
19	64	64	64	64	64	16	16	16	5.25	31.25	5.24	7.67	7.99	2.28	−19.10
20	64	64	64	64	64	64	4	4	5	25	9.00	9.85	8.93	2.33	−20.10
21	64	64	64	64	64	64	16	4	5.25	31.25	7.39	8.34	7.44	0.83	−21.90
22	64	64	64	64	64	64	16	16	5.5	37.5	5.12	6.37	5.69	−0.81	−23.81
23	64	64	64	64	64	64	64	4	5.5	37.5	5.69	5.82	4.42	−2.69	−27.10
24	64	64	64	64	64	64	64	16	5.75	43.75	3.97	4.22	2.91	−4.11	−28.83
25	64	64	64	64	64	64	64	64	6	50	1.68	1.41	−0.29	−7.61	−33.08