APPARATUS AND METHOD FOR REDUCING PEAK TO AVERAGE POWER RATIO IN AN ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING SYSTEM

• US 20080298490A1
• Filed: 06/04/2008
• Published: 12/04/2008
• Est. Priority Date: 06/04/2007
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Hak-Ju, MYUNG, Se-Ho, KIM, Jae-Yoel, YUN, Sung-Ryul, JEONG, Hong-Sil
• Granted Patent: US 8,300,714 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04L 27/2618 Reduction thereof using auxiliary subcarriers
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver

Abstract

A method for reducing a Peak to Average Power Ratio (PAPR) using reserved tones in a transmission apparatus of an Orthogonal Frequency Division Multiplexing (OFDM) communication system is provided. The method includes detecting a subcarrier spacing interval and the number of spaced symbols based on a predetermined pilot pattern upon signal reception, and determining positions of shifted reserved tones obtained by shifting positions of reserved tones allocated to a predetermined symbol during the number of the spaced symbols at intervals of the spacing interval; determining an impulse waveform obtained by rotating a phase of a complex value of an impulse stored in a memory, using the determined positions of frequency-domain reserved tones of each symbol; calculating a subtrahend for a PAPR of an output signal using the phase-rotated impulse waveform; and reducing a PAPR of an input signal by performing a gradient algorithm using the phase-rotated impulse waveform.

Claims

1. A method for reducing a Peak to Average Power Ratio (PAPR) using reserved tones in a transmission apparatus of an Orthogonal Frequency Division Multiplexing (OFDM) communication system, the method comprising:

detecting a subcarrier spacing interval and a number of spaced symbols based on a predetermined pilot pattern, and determining positions of shifted reserved tones according to the detected subcarrier spacing interval and the number of spaced symbols;

determining an impulse waveform obtained by rotating a phase of a complex value of an impulse stored in a memory, using the determined positions of frequency-domain reserved tones of each symbol;

calculating a subtrahend for a PAPR of an output signal using the phase-rotated impulse waveform; and

reducing a PAPR of an input signal by performing a gradient algorithm using the phase-rotated impulse waveform.

2. The method of claim 1, wherein the positions of shifted reserved tones are calculated using the following:

S_l={i_k+x*(l mod y)|i_k ∈

S₀,0≦

k<

N_RT,0≦

l<

D_L}

where k denotes an index of a tone reservation unit, L is a number of subcarriers, S₀ denotes a position of a predetermined reserved tone, N_RT denotes the number of reserved tones, D_L denotes the number of data symbols, x denotes a spacing interval of a subcarrier based on a pilot pattern, and y denotes the number of spaced symbols based on the pilot pattern.

3. The method of claim 2, wherein positions of reserved tones based on a predetermined symbol are positions corresponding to subcarrier tone indexes shown in the following table:

FFT size (Number of reserved carriers) Reserved Carrier Indices  

1K (10) 109, 117, 122, 129, 139, 321, 350, 403, 459, 465  

2K (18) 250, 404, 638, 677, 700, 712, 755, 952, 1125, 1145, 1190, 1276, 1325, 1335, 1406, 1431, 1472, 1481  

4K (36) 170, 219, 405, 501, 597, 654, 661, 745, 995, 1025, 1319, 1361, 1394, 1623, 1658, 1913, 1961, 1971, 2106, 2117, 2222, 2228, 2246, 2254, 2361, 2468, 2469, 2482, 2637, 2679, 2708, 2825, 2915, 2996, 3033, 3119  

8K (72) 111, 115, 123, 215, 229, 392, 613, 658, 831, 842, 997, 1503, 1626, 1916, 1924, 1961, 2233, 2246, 2302, 2331, 2778, 2822, 2913, 2927, 2963, 2994, 3087, 3162, 3226, 3270, 3503, 3585, 3711, 3738, 3874, 3902, 4013, 4017, 4186, 4253, 4292, 4339, 4412, 4453, 4669, 4910, 5015, 5030, 5061, 5170, 5263, 5313, 5360, 5384, 5394, 5493, 5550, 5847, 5901, 5999, 6020, 6165, 6174, 6227, 6245, 6314, 6316, 6327, 6503, 6507, 6545, 6565 16K (144) 109, 122, 139, 171, 213, 214, 251, 585, 763, 1012, 1021, 1077, 1148, 1472, 1792, 1883, 1889, 1895, 1900, 2013, 2311, 2582, 2860, 2980, 3011, 3099, 3143, 3171, 3197, 3243, 3257, 3270, 3315, 3436, 3470, 3582, 3681, 3712, 3767, 3802, 3979, 4045, 4112, 4197, 4409, 4462, 4756, 5003, 5007, 5036, 5246, 5483, 5535, 5584, 5787, 5789, 6047, 6349, 6392, 6498, 6526, 6542, 6591, 6680, 6688, 6785, 6860, 7134, 7286, 7387, 7415, 7417, 7505, 7526, 7541, 7551, 7556, 7747, 7814, 7861, 7880, 8045, 8179, 8374, 8451, 8514, 8684, 8698, 8804, 8924, 9027, 9113, 9211, 9330, 9479, 9482, 9487, 9619, 9829, 10326, 10394, 10407, 10450, 10528, 10671, 10746, 10774, 10799, 10801, 10912, 11113, 11128, 11205, 11379, 11459, 11468, 11658, 11776, 11791, 11953, 11959, 12021, 12028, 12135, 12233, 12407, 12441, 12448, 12470, 12501, 12548, 12642, 12679, 12770, 12788, 12899, 12923, 12939, 13050, 13103, 13147, 13256, 13339, 13409 32K (288) 164, 320, 350, 521, 527, 578, 590, 619, 635, 651, 662, 664, 676, 691, 723, 940, 1280, 1326, 1509, 1520, 1638, 1682, 1805, 1833, 1861, 1891, 1900, 1902, 1949, 1967, 1978, 1998, 2006, 2087, 2134, 2165, 2212, 2427, 2475, 2555, 2874, 3067, 3091, 3101, 3146, 3188, 3322, 3353, 3383, 3503, 3523, 3654, 3856, 4150, 4158, 4159, 4174, 4206, 4318, 4417, 4629, 4631, 4875, 5104, 5106, 5111, 5131, 5145, 5146, 5177, 5181, 5246, 5269, 5458, 5474, 5500, 5509, 5579, 5810, 5823, 6058, 6066, 6098, 6411, 6741, 6775, 6932, 7103, 7258, 7303, 7413, 7586, 7591, 7634, 7636, 7655, 7671, 7675, 7756, 7760, 7826, 7931, 7937, 7951, 8017, 8061, 8071, 8117, 8317, 8321, 8353, 8806, 9010, 9237, 9427, 9453, 9469, 9525, 9558, 9574, 9584, 9820, 9973, 10011, 10043, 10064, 10066, 10081, 10136, 10193, 10249, 10511, 10537, 11083, 11350, 11369, 11428, 11622, 11720, 11924, 11974, 11979, 12944, 12945, 13009, 13070, 13110, 13257, 13364, 13370, 13449, 13503, 13514, 13520, 13583, 13593, 13708, 13925, 14192, 14228, 14235, 14279, 14284, 14370, 14393, 14407, 14422, 14471, 14494, 14536, 14617, 14829, 14915, 15094, 15138, 15155, 15170, 15260, 15283, 15435, 15594, 15634, 15810, 16178, 16192, 16196, 16297, 16366, 16498, 16501, 16861, 16966, 17039, 17057, 17240, 17523, 17767, 18094, 18130, 18218, 18344, 18374, 18657, 18679, 18746, 18772, 18779, 18786, 18874, 18884, 18955, 19143, 19497, 19534, 19679, 19729, 19738, 19751, 19910, 19913, 20144, 20188, 20194, 20359, 20490, 20500, 20555, 20594, 20633, 20656, 21099, 21115, 21597, 22139, 22208, 22244, 22530, 22547, 22562, 22567, 22696, 22757, 22798, 22854, 22877, 23068, 23102, 23141, 23154, 23170, 23202, 23368, 23864, 24057, 24215, 24219, 24257, 24271, 24325, 24447, 25137, 25590, 25702, 25706, 25744, 25763, 25811, 25842, 25853, 25954, 26079, 26158, 26285, 26346, 26488, 26598, 26812, 26845, 26852, 26869, 26898, 26909, 26927, 26931, 26946, 26975, 26991, 27039

4. A transmission apparatus for reducing a Peak to Average Power Ratio (PAPR) using reserved tones in an Orthogonal Frequency Division Multiplexing (OFDM) communication system, the apparatus comprising:

a memory for storing a number of and positions of reserved tones allocated to a predetermined symbol, and an impulse waveform based on the positions of the reserved tones;

a controller for detecting a subcarrier spacing interval and a number of spaced symbols based on a predetermined pilot pattern, determining positions of shifted reserved tones according to the detected subcarrier spacing interval and the number of spaced symbols, and determining a new impulse waveform generated by rotating a phase of a complex value according to the determined positions of the shifted reserved tones;

a tone reservation unit for reserving data, pilots, and the reserved tones in a subcarrier position for every symbol according to a control signal from the controller; and

a gradient algorithm unit for calculating a subtrahend for a PAPR using an updated impulse waveform received from the controller, and adding the calculated subtrahend for the PAPR to an input signal.

5. The transmission apparatus of claim 4, wherein the controller calculates the positions of shifted reserved tones using the following:

S_l={i_k+x*(l mod y)|i_k ∈

S₀,0≦

k<

N_RT,0≦

l<

D_L}

where k denotes an index of the tone reservation unit, L is a number of subcarriers, S₀ denotes a position of a predetermined reserved tone, N_RT denotes the number of reserved tones, D_L denotes the number of data symbols, x denotes a spacing interval of a subcarrier based on a pilot pattern, and y denotes the number of spaced symbols based on the pilot pattern.

6. The transmission apparatus of claim 5, wherein positions of reserved tones based on a predetermined symbol are positions corresponding to subcarrier tone indexes shown in the following table:

FFT size (Number of reserved carriers) Reserved Carrier Indices  

1K (10) 109, 117, 122, 129, 139, 321, 350, 403, 459, 465  

2K (18) 250, 404, 638, 677, 700, 712, 755, 952, 1125, 1145, 1190, 1276, 1325, 1335, 1406, 1431, 1472, 1481  

4K (36) 170, 219, 405, 501, 597, 654, 661, 745, 995, 1025, 1319, 1361, 1394, 1623, 1658, 1913, 1961, 1971, 2106, 2117, 2222, 2228, 2246, 2254, 2361, 2468, 2469, 2482, 2637, 2679, 2708, 2825, 2915, 2996, 3033, 3119  

8K (72) 111, 115, 123, 215, 229, 392, 613, 658, 831, 842, 997, 1503, 1626, 1916, 1924, 1961, 2233, 2246, 2302, 2331, 2778, 2822, 2913, 2927, 2963, 2994, 3087, 3162, 3226, 3270, 3503, 3585, 3711, 3738, 3874, 3902, 4013, 4017, 4186, 4253, 4292, 4339, 4412, 4453, 4669, 4910, 5015, 5030, 5061, 5170, 5263, 5313, 5360, 5384, 5394, 5493, 5550, 5847, 5901, 5999, 6020, 6165, 6174, 6227, 6245, 6314, 6316, 6327, 6503, 6507, 6545, 6565 16K (144) 109, 122, 139, 171, 213, 214, 251, 585, 763, 1012, 1021, 1077, 1148, 1472, 1792, 1883, 1889, 1895, 1900, 2013, 2311, 2582, 2860, 2980, 3011, 3099, 3143, 3171, 3197, 3243, 3257, 3270, 3315, 3436, 3470, 3582, 3681, 3712, 3767, 3802, 3979, 4045, 4112, 4197, 4409, 4462, 4756, 5003, 5007, 5036, 5246, 5483, 5535, 5584, 5787, 5789, 6047, 6349, 6392, 6498, 6526, 6542, 6591, 6680, 6688, 6785, 6860, 7134, 7286, 7387, 7415, 7417, 7505, 7526, 7541, 7551, 7556, 7747, 7814, 7861, 7880, 8045, 8179, 8374, 8451, 8514, 8684, 8698, 8804, 8924, 9027, 9113, 9211, 9330, 9479, 9482, 9487, 9619, 9829, 10326, 10394, 10407, 10450, 10528, 10671, 10746, 10774, 10799, 10801, 10912, 11113, 11128, 11205, 11379, 11459, 11468, 11658, 11776, 11791, 11953, 11959, 12021, 12028, 12135, 12233, 12407, 12441, 12448, 12470, 12501, 12548, 12642, 12679, 12770, 12788, 12899, 12923, 12939, 13050, 13103, 13147, 13256, 13339, 13409 32K (288) 164, 320, 350, 521, 527, 578, 590, 619, 635, 651, 662, 664, 676, 691, 723, 940, 1280, 1326, 1509, 1520, 1638, 1682, 1805, 1833, 1861, 1891, 1900, 1902, 1949, 1967, 1978, 1998, 2006, 2087, 2134, 2165, 2212, 2427, 2475, 2555, 2874, 3067, 3091, 3101, 3146, 3188, 3322, 3353, 3383, 3503, 3523, 3654, 3856, 4150, 4158, 4159, 4174, 4206, 4318, 4417, 4629, 4631, 4875, 5104, 5106, 5111, 5131, 5145, 5146, 5177, 5181, 5246, 5269, 5458, 5474, 5500, 5509, 5579, 5810, 5823, 6058, 6066, 6098, 6411, 6741, 6775, 6932, 7103, 7258, 7303, 7413, 7586, 7591, 7634, 7636, 7655, 7671, 7675, 7756, 7760, 7826, 7931, 7937, 7951, 8017, 8061, 8071, 8117, 8317, 8321, 8353, 8806, 9010, 9237, 9427, 9453, 9469, 9525, 9558, 9574, 9584, 9820, 9973, 10011, 10043, 10064, 10066, 10081, 10136, 10193, 10249, 10511, 10537, 11083, 11350, 11369, 11428, 11622, 11720, 11924, 11974, 11979, 12944, 12945, 13009, 13070, 13110, 13257, 13364, 13370, 13449, 13503, 13514, 13520, 13583, 13593, 13708, 13925, 14192, 14228, 14235, 14279, 14284, 14370, 14393, 14407, 14422, 14471, 14494, 14536, 14617, 14829, 14915, 15094, 15138, 15155, 15170, 15260, 15283, 15435, 15594, 15634, 15810, 16178, 16192, 16196, 16297, 16366, 16498, 16501, 16861, 16966, 17039, 17057, 17240, 17523, 17767, 18094, 18130, 18218, 18344, 18374, 18657, 18679, 18746, 18772, 18779, 18786, 18874, 18884, 18955, 19143, 19497, 19534, 19679, 19729, 19738, 19751, 19910, 19913, 20144, 20188, 20194, 20359, 20490, 20500, 20555, 20594, 20633, 20656, 21099, 21115, 21597, 22139, 22208, 22244, 22530, 22547, 22562, 22567, 22696, 22757, 22798, 22854, 22877, 23068, 23102, 23141, 23154, 23170, 23202, 23368, 23864, 24057, 24215, 24219, 24257, 24271, 24325, 24447, 25137, 25590, 25702, 25706, 25744, 25763, 25811, 25842, 25853, 25954, 26079, 26158, 26285, 26346, 26488, 26598, 26812, 26845, 26852, 26869, 26898, 26909, 26927, 26931, 26946, 26975, 26991, 27039

7. A method for reducing a Peak to Average Power Ratio (PAPR) using reserved tones in a reception apparatus of an Orthogonal Frequency Division Multiplexing (OFDM) communication system, the method comprising:

detecting a subcarrier spacing interval and a number of spaced symbols based on a predetermined scattered pilot pattern, and determining positions of shifted reserved tones according to the detected subcarrier spacing interval and the number of spaced symbols;

extracting data signals transmitted in positions except for the reserved tone positions in every symbol using the determined reserved tone positions; and

performing a demodulation on the extracted data signals.

8. The method of claim 7, wherein the positions of shifted reserved tones are calculated using the following equation,

S_l={i_k+x*(l mod y)|i_k ∈

S₀,0≦

k<

N_RT,0≦

l<

D_L}

where k denotes an index of a tone reservation unit, L is a number of subcarriers, S₀ denotes a position of a predetermined reserved tone, N_RT denotes the number of reserved tones, D_L denotes the number of data symbols, x denotes a spacing interval of a subcarrier based on a pilot pattern, and y denotes the number of spaced symbols based on the pilot pattern.

9. The method of claim 8, wherein positions of reserved tones based on a predetermined symbol are positions corresponding to subcarrier tone indexes shown in the following table,

FFT size (Number of reserved carriers) Reserved Carrier Indices  

10. A reception apparatus for reducing a Peak to Average Power Ratio (PAPR) using reserved tones in an Orthogonal Frequency Division Multiplexing (OFDM) communication system, the apparatus comprising:

a memory for storing a number of and positions of reserved tones allocated to a predetermined symbol;

a controller for detecting a subcarrier spacing interval and a number of spaced symbols based on a predetermined scattered pilot pattern, and determining positions of shifted reserved tones according to the detected subcarrier spacing interval and the number of spaced symbols;

a data tone signal extractor for extracting data signals transmitted in positions except for the reserved tone positions in every symbol using information on the reserved tone positions received from the controller; and

a data demodulator for performing demodulation on signals output from the data tone signal extractor.

11. The reception apparatus of claim 10, wherein the controller calculates the positions of shifted reserved tones using the following equation,

S_l={i_k+x*(l mod y)|i_k ∈

S₀,0≦

k<

N_RT,0≦

l<

D_L}

where k denotes an index of the tone reservation unit, L is a number of subcarriers, S₀ denotes a position of a predetermined reserved tone, N_RT denotes the number of reserved tones, D_L denotes the number of data symbols, x denotes a spacing interval of a subcarrier based on a pilot pattern, and y denotes the number of spaced symbols based on the pilot pattern.

12. The reception apparatus of claim 11, wherein positions of reserved tones based on a predetermined symbol are positions corresponding to subcarrier tone indexes shown in the following table;

FFT size (Number of reserved carriers) Reserved Carrier Indices  

1K (10) 109, 117, 122, 129, 139, 321, 350, 403, 459, 465  

2K (18) 250, 404, 638, 677, 700, 712, 755, 952, 1125, 1145, 1190, 1276, 1325, 1335, 1406, 1431, 1472, 1481  

4K (36) 170, 219, 405, 501, 597, 654, 661, 745, 995, 1025, 1319, 1361, 1394, 1623, 1658, 1913, 1961, 1971, 2106, 2117, 2222, 2228, 2246, 2254, 2361, 2468, 2469, 2482, 2637, 2679, 2708, 2825, 2915, 2996, 3033, 3119  

8K (72) 111, 115, 123, 215, 229, 392, 613, 658, 831, 842, 997, 1503, 1626, 1916, 1924, 1961, 2233, 2246, 2302, 2331, 2778, 2822, 2913, 2927, 2963, 2994, 3087, 3162, 3226, 3270, 3503, 3585, 3711, 3738, 3874, 3902, 4013, 4017, 4186, 4253, 4292, 4339, 4412, 4453, 4669, 4910, 5015, 5030, 5061, 5170, 5263, 5313, 5360, 5384, 5394, 5493, 5550, 5847, 5901, 5999, 6020, 6165, 6174, 6227, 6245, 6314, 6316, 6327, 6503, 6507, 6545, 6565 16K (144) 109, 122, 139, 171, 213, 214, 251, 585, 763, 1012, 1021, 1077, 1148, 1472, 1792, 1883, 1889, 1895, 1900, 2013, 2311, 2582, 2860, 2980, 3011, 3099, 3143, 3171, 3197, 3243, 3257, 3270, 3315, 3436, 3470, 3582, 3681, 3712, 3767, 3802, 3979, 4045, 4112, 4197, 4409, 4462, 4756, 5003, 5007, 5036, 5246, 5483, 5535, 5584, 5787, 5789, 6047, 6349, 6392, 6498, 6526, 6542, 6591, 6680, 6688, 6785, 6860, 7134, 7286, 7387, 7415, 7417, 7505, 7526, 7541, 7551, 7556, 7747, 7814, 7861, 7880, 8045, 8179, 8374, 8451, 8514, 8684, 8698, 8804, 8924, 9027, 9113, 9211, 9330, 9479, 9482, 9487, 9619, 9829, 10326, 10394, 10407, 10450, 10528, 10671, 10746, 10774, 10799, 10801, 10912, 11113, 11128, 11205, 11379, 11459, 11468, 11658, 11776, 11791, 11953, 11959, 12021, 12028, 12135, 12233, 12407, 12441, 12448, 12470, 12501, 12548, 12642, 12679, 12770, 12788, 12899, 12923, 12939, 13050, 13103, 13147, 13256, 13339, 13409 32K (288) 164, 320, 350, 521, 527, 578, 590, 619, 635, 651, 662, 664, 676, 691, 723, 940, 1280, 1326, 1509, 1520, 1638, 1682, 1805, 1833, 1861, 1891, 1900, 1902, 1949, 1967, 1978, 1998, 2006, 2087, 2134, 2165, 2212, 2427, 2475, 2555, 2874, 3067, 3091, 3101, 3146, 3188, 3322, 3353, 3383, 3503, 3523, 3654, 3856, 4150, 4158, 4159, 4174, 4206, 4318, 4417, 4629, 4631, 4875, 5104, 5106, 5111, 5131, 5145, 5146, 5177, 5181, 5246, 5269, 5458, 5474, 5500, 5509, 5579, 5810, 5823, 6058, 6066, 6098, 6411, 6741, 6775, 6932, 7103, 7258, 7303, 7413, 7586, 7591, 7634, 7636, 7655, 7671, 7675, 7756, 7760, 7826, 7931, 7937, 7951, 8017, 8061, 8071, 8117, 8317, 8321, 8353, 8806, 9010, 9237, 9427, 9453, 9469, 9525, 9558, 9574, 9584, 9820, 9973, 10011, 10043, 10064, 10066, 10081, 10136, 10193, 10249, 10511, 10537, 11083, 11350, 11369, 11428, 11622, 11720, 11924, 11974, 11979, 12944, 12945, 13009, 13070, 13110, 13257, 13364, 13370, 13449, 13503, 13514, 13520, 13583, 13593, 13708, 13925, 14192, 14228, 14235, 14279, 14284, 14370, 14393, 14407, 14422, 14471, 14494, 14536, 14617, 14829, 14915, 15094, 15138, 15155, 15170, 15260, 15283, 15435, 15594, 15634, 15810, 16178, 16192, 16196, 16297, 16366, 16498, 16501, 16861, 16966, 17039, 17057, 17240, 17523, 17767, 18094, 18130, 18218, 18344, 18374, 18657, 18679, 18746, 18772, 18779, 18786, 18874, 18884, 18955, 19143, 19497, 19534, 19679, 19729, 19738, 19751, 19910, 19913, 20144, 20188, 20194, 20359, 20490, 20500, 20555, 20594, 20633, 20656, 21099, 21115, 21597, 22139, 22208, 22244, 22530, 22547, 22562, 22567, 22696, 22757, 22798, 22854, 22877, 23068, 23102, 23141, 23154, 23170, 23202, 23368, 23864, 24057, 24215, 24219, 24257, 24271, 24325, 24447, 25137, 25590, 25702, 25706, 25744, 25763, 25811, 25842, 25853, 25954, 26079, 26158, 26285, 26346, 26488, 26598, 26812, 26845, 26852, 26869, 26898, 26909, 26927, 26931, 26946, 26975, 26991, 27039