1. Tubeless steel wheel for vehicles intended for the transport of loads or large number of passengers, such as trucks or buses, the wheel comprised of a rim (1), a disk (2) and a valve (8), wherein the rim (1) is sized equal or greater than about 5.25 inches in width, the rim (1) comprising, from the side where the disk (2) is mounted, a rim flange (6), adjacent to a bead seat (5), the bead seat (5) being adjacent to a first rim ledge (7), the first ledge (7) joining a ramp (9), the ramp (9) being adjacent to a second ledge (4), which joins a rim ledge (3) by means of a side wall (13), the disk (2) containing an end portion (21) associated to the second rim ledge (4), the wheel being characterized by comprising a valve hole (11) is disposed at a junction point (10) formed at the intersection between the bead seat (5) and the first ledge (7).
2. Wheel according to claim 1 characterized wherein first ledge (7) adjacent to the bead seat (5) on the side of the disk (2) has a length \u201cL\u201d, with diameter equal to that of the start of the bead seat (5) and also, the diameter of the wheel is \u03c6N, where the ratio
L\u03c6N\xd71000
is equal or greater than 37.
3. Wheel according to claim 1 characterized wherein a valve (8) has a seating angle of 25\xb0 in relation to the axis of the abscissas.
4. Wheel according to claim 1 characterized wherein a valve (8) has an exit angle (\u03b1) of 65\xb0, forming an end positioning angle of 0\xb0 in relation to the axis of the wheel.
5. Tubeless steel wheel for vehicles intended for the transport of loads or large number of passengers, such as trucks or buses, the wheel comprising a rim (1), a disk (2) and a valve (8) and the rim (1) is sized equal or greater than about 5.25 inches in width, the rim (1) comprising, from the side where the disk (2) is mounted, a rim flange (6), adjacent to a bead seat (5), the bead seat (5) being adjacent to a first rim ledge (7), the first ledge (7) joining a ramp (9), the ramp (9) being adjacent to a second ledge (4), which joins a rim ledge (3) by means of a side wall (13), the disk (2) containing an end portion (21) associated to the second rim ledge (4), \u03c6D the diameter of the surface being radially inside the rim ledge (3) of the rim (1), \u03c6M the diameter of the surface being radially inside the second ledge (4), diameter taken axially to the end of the disk (2) de wheel (1), and \u03c6B the diameter of the surface being radially lower than the start of the bead seats (5,15), diameters taken axially at the point of junction (10) of the reference plans of the bead seat (5), adjacent to the first ledge (7) of the rim, the wheel (1) being characterized by the fact that the ratio
R
=
(
\u03c6
M
–
\u03c6
D
)
(
\u03c6
B
–
\u03c6
D
)
is equal or less than 0.60.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for adaptively reducing a peak-to-average power ratio in a communication system, the method comprising:
clipping energy from at least one peak of a modulated signal, the modulated signal including a plurality of sub-carriers;
adaptively selecting at least one data sub-carrier for peak-to-average power ratio reduction use based on known scheduling information; and
distributing the clipped energy among the at least one data sub-carrier.
2. The method of claim 1, wherein the modulated signal includes an orthogonal frequency division multiplexing symbol.
3. The method of claim 2, wherein the sub-carriers are modulated using a plurality of modulation schemes.
4. The method of claim 2, further comprising distributing the clipped energy among at least one reserved sub-carrier.
5. The method of claim 2, further comprising:
assigning communication devices to data sub-carriers;
mapping the orthogonal frequency division multiplexing symbol onto the modulated signal; and
determining the at least one data sub-carrier for distributing the clipped energy based on assigning the communication devices.
6. The method of claim 5, further comprising:
transforming the clipped signal for use in a frequency domain;
filtering the transformed signal using an F-filter;
transforming the filtered signal for use in a time domain; and
combining the transformed filtered signal with the modulated signal to produce an output signal having a peak-to-average power ratio less than the peak-to-average power ratio of the modulated signal.
7. The method of claim 6, wherein:
the F-filter is constructed in the frequency domain; and
the F-filter includes a weighted coefficient for each sub-carrier.
8. The method of claim 7, wherein the coefficient for each sub-carrier is determined based on assigning the communication devices, a total amount of sub-carriers for the modulated signal, an amount of sub-carriers for each modulation scheme, an amount of reserved sub-carriers and signal quality parameters.
9. The method of claim 8, wherein the signal quality parameters include the peak-to-average power ratio for the output signal and residual constellation error for each sub-carrier.
10. The method of claim 5, further comprising:
filtering the clipped modulated signal using a g-function; and
combining the filtered signal with the clipped modulated signal to produce an output signal having a peak-to-average power ratio less than the peak-to-average power ratio of the modulated signal.
11. The method of claim 10, wherein the g-function is constructed by:
constructing an F-filter in a frequency domain, the F-filter including a weighted coefficient for each sub-carrier; and
transforming the F-filter to a g-function for use in a time domain.
12. The method of claim 11, wherein the coefficient for each sub-carrier is determined based on the based on assigning the communication devices, a total amount of sub-carriers for the modulated signal, an amount of sub-carriers for each modulation scheme, an amount of reserved sub-carriers and signal quality parameters.
13. A system for adaptively reducing a peak-to-average power ratio in a communication system, the system comprising:
a scheduler operating to adaptively select at least one data sub-carrier for peak to average power ratio reduction;
a clipper, operating to clip energy from at least one peak of a modulated signal, the modulated signal including an orthogonal frequency division multiplexing symbol having a plurality of sub-carriers; and
a filter, communicatively coupled to the scheduler and to the clipper, the filter operating to adaptively distribute the clipped energy among the at least one data sub-carrier.
14. The system of claim 13, wherein the filter further operates to adaptively distribute the clipped energy among at least one reserved sub-carrier.
15. The system of claim 14, further comprising a filter generator communicatively coupled to the scheduler, the filter generator operating to create the filter, and wherein the scheduler further operates to:
assign communication devices to data sub-carriers;
map the orthogonal frequency division multiplexing symbol onto the modulated signal; and
determine the at least one data sub-carrier for distributing the clipped energy based on assigning the communication devices.
16. The system of claim 15, wherein the filter is an F-filter, the F-filter including a weighted coefficient for each sub-carrier, the system further comprising:
a fast Fourier transform communicatively coupled to the clipper and to the filter, the fast Fourier transform operating to transform the clipped modulated signal for use in a frequency domain;
an inverse fast Fourier transform communicatively coupled to the filter, the inverse fast Fourier transform operating to transform the filtered clipped signal for use in a time domain; and
a subtracter, communicatively coupled to the inverse fast Fourier transform and to the clipper, the subtracter operating to combine the transformed filtered clipped signal with the modulated signal to produce an output signal having a peak-to-average power ratio less than the peak-to-average power ratio of the modulated signal.
17. The system of claim 16, wherein the filter generator determines the coefficient for each sub-carrier based on assigning the communication devices, a total amount of sub-carriers for the modulated signal, an amount of sub-carriers for each modulation scheme, an amount of reserved sub-carriers, the peak-to-average power ratio for the output signal and residual constellation error for each sub-carrier.
18. The system of claim 17, further comprising a configuration unit communicatively coupled to the scheduler and to the filter generator, the configuration unit operating to:
determine a number of iterations and a clipping threshold for the clipper;
determine a re-growth control factor; and
define a maximum and a minimum amount of sub-carriers available for peak-to-average power ratio reduction.
19. The system of claim 15, wherein the filter is a g-function, the filter generator operating to construct an F-filter in a frequency domain, the F-filter including a weighted coefficient for each sub-carrier, the system further comprising:
an inverse fast Fourier transform communicatively coupled to the filter generator and to the filter, the inverse fast Fourier transform operating to transform the F-filter to the g-function for use in a time domain; and
a subtracter, communicatively coupled to filter and to the clipper, the subtracter operating to combine the filtered clipped signal with the modulated signal to produce an output signal having a peak-to-average power ratio less than the peak-to-average power ratio of the modulated signal.
20. The system of claim 19, wherein the coefficient for each sub-carrier is determined based on assigning the communication devices, a total amount of sub-carriers for the modulated signal, an amount of sub-carriers for each modulation scheme, an amount of reserved sub-carriers and signal quality parameters.