1. A method of performing channel status information feedback using a hierarchical codebook, comprising:
generating a hierarchical codebook;
configuring the generated hierarchical codebook to a transmitting end and a receiving end, respectively; and
feeding back the channel status information from the receiving end to the transmitting end based on the hierarchical codebook.
2. The method according to claim 1, wherein the step of generating a hierarchical codebook further comprises the following steps:
i) dividing each level of codeword in a to-be-generated codebook into a plurality of segments based on a basic codebook;
ii) generating each level of codeword in a first stage, wherein the each level of codeword is selected from the basic codebook; and
iii) generating each level of codeword in other stages, wherein the each level of codeword is selected a pre-provided training sample matrix.
3. The method according to claim 2, wherein between the step i) and the step ii) is further comprises a step of: for each divided stage, predefining codebook generation constraints suitable for the stage.
4. The method according to claim 3, wherein the codebook generation constraints for the first stage comprise compatibility to the basic code or inheriting good codebook properties, wherein the codebook generation constraints for other stages comprise optimizing system performances.
5. (canceled)
6. The method according to claim 2, wherein a codeword for each level is selected from the basic codebook or from the training samples based on a particular performance metric.
7. The method according to claim 6, wherein the particular performance metric includes one of the following items: capacity maximization, minimum even square error, minimum distance, maximum signal-to-noise ratio, maximum signal-to-interference plus noise ratio, maximum signal-to-interference ratio.
8. (canceled)
9. (canceled)
10. The method according to claim 1, wherein the step of feeding back the channel status information from the receiving end to the transmitting end based on the hierarchical codebook further comprises the following step:
using a first bit and a second bit of the feedback bits to represent a signaling for performing tree search to the hierarchical codebook.
11. The method according to claim 10, wherein the step of feeding back the channel status information from the receiving end to the transmitting end based on the hierarchical codebook further comprises the following step:
comparing a binary word of a vector of the current feedback time interval n with a binary word of a vector of the preceding time interval n\u22121;
determining the feedback bit based on the comparison result.
12. A system of performing channel status information feedback using a hierarchical codebook, comprising:
a module configured to generate a hierarchical codebook;
a module configured to configure the generated hierarchical codebook to a transmitting end and a receiving end, respectively; and
a module configured to feed back the channel status information from the receiving end to the transmitting end based on the hierarchical codebook.
13. The system according to claim 12, wherein the module configured to generate a hierarchical codebook further comprises:
i) a module configured to divide each level of codeword in a to-be-generated codebook into a plurality of segments based on a basic codebook;
ii) a module configured to generate each level of codeword in a first stage, wherein the each level of codeword is selected from the basic codebook; and
iii) a module configured to generate each level of codeword in other stages, wherein the each level of codeword is selected a pre-provided training sample matrix.
14. The system according to claim 13, further comprising a module configured to for each divided stage, predefine codebook generation constraints suitable for the stage.
15. The system according to claim 14, wherein the codebook generation constraints for the first stage comprise compatibility to the basic code or inheriting good codebook properties wherein
the codebook generation constraints for other stages comprise optimizing system performances.
16. (canceled)
17. The system according to claim 13, wherein the module configured to generate each level of codeword in the first stage and the module configured to generate each level of codeword in other stages select a codeword for each level from the basic codebook or from the training sample based on a particular performance metric, wherein the particular performance metric includes one of the following terms: capacity maximization, minimum even square error, minimum distance, maximum signal-to-noise ratio, maximum signaI-to-interference plus noise ratio, maximum signaI-to-interference ratio.
18. (canceled)
19. (canceled)
20. (canceled)
21. The system according to claim 12, wherein the module configured to feed back the channel status information from the receiving end to the transmitting end based on the hierarchical codebook further comprises:
a module configured to use a first bit and a second bit of the feedback bits to represent a signaling for performing tree search to the hierarchical codebook.
22. The system according to claim 21, wherein the module configured to feed back the channel status information from the receiving end to the transmitting end based on the hierarchical codebook further comprises:
a module configured to compare a binary word of a vector of the current feedback time interval n with a binary word of a vector of the preceding time interval n\u22121;
a module configured to determine the feedback bit based on the comparison result.
23. (canceled)
24. (canceled)
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
That which is claimed is:
1. A hydraulic circuit for a working vehicle which includes a working machine, said hydraulic circuit comprising:
a working machine hydraulic pump for providing an operating oil pressure Pw;
a working machine hydraulic circuit for conducting a hydraulic drive of the working machine by receiving pressurized oil which is discharged from said working machine hydraulic pump and which is at said operating oil pressure Pw;
a steering hydraulic pump;
a steering hydraulic circuit for conducting hydraulic drive of a steering operation by receiving pressurized oil which is discharged from said steering hydraulic pump at a steering oil pressure Pst;
a variable displacement auxiliary hydraulic pump in which displacement volume becomes smaller as the operating oil pressure Pw becomes higher when the operating oil pressure Pw exceeds a predetermined oil pressure value Pu by receiving the operating oil pressure Pw of the working machine hydraulic circuit; and
a flow dividing valve for switching and supplying oil discharged from said auxiliary hydraulic pump to either of the working machine hydraulic circuit and the steering hydraulic circuit, with a priority being given to the steering hydraulic circuit.
2. A hydraulic circuit for a working vehicle in accordance with claim 1, wherein said variable displacement auxiliary hydraulic pump has: a servo cylinder, for varying the displacement of said variable displacement auxiliary hydraulic pump; a control valve for operating said servo cylinder, said control valve having a pressure receiving surface; and conduit means for supplying to said pressure receiving surface the operating oil pressure Pw from said working machine hydraulic circuit.
3. A hydraulic circuit for a working vehicle in accordance with claim 1, wherein said variable displacement auxiliary hydraulic pump is an electromagnetic variable displacement auxiliary hydraulic pump in which the displacement volume is variable responsive to an exciting current;
further comprising:
an operating oil pressure detecting means for detecting the operating oil pressure Pw of the working machine hydraulic circuit; and
an exciting current generating means for storing the predetermined oil pressure value Pu, for generating the exciting current which makes the displacement volume smaller as the operating oil pressure Pw becomes higher, and for inputting the exciting current to the auxiliary hydraulic pump when the operating oil pressure Pw exceeds said predetermined oil pressure value Pu by receiving the operating oil pressure Pw from the operating oil pressure detecting means.
4. A hydraulic circuit for a working vehicle in accordance with claim 1, wherein said variable displacement auxiliary hydraulic pump has an operating oil pressure receiving surface area Aw, for receiving operating oil pressure Pw of the working machine hydraulic circuit, and a separate steering oil pressure receiving surface area Ast, for receiving steering oil pressure Pst of the steering hydraulic circuit with a relationship Aw>Ast, and wherein the displacement volume of said variable displacement auxiliary hydraulic pump becomes smaller as the value of (Pw*Aw)(Pst*Ast) becomes greater when (Pw*Aw)(Pst*Ast) exceeds a predetermined value.
5. A hydraulic circuit for a working vehicle in accordance with claim 1, where said variable displacement auxiliary hydraulic pump is an electromagnetic variable displacement auxiliary hydraulic pump in which the displacement volume is variable responsive to an exciting current;
further comprising:
an operating oil pressure detecting means for detecting operating oil pressure Pw of the working machine hydraulic circuit;
a steering oil pressure detecting means for detecting steering oil pressure Pst of the steering hydraulic circuit; and
an exciting current generating means, for previously storing the predetermined oil pressure Pu, for computing (Pwk*Pst) (where k<1) by receiving the operating oil pressure Pw from the operating oil pressure detecting means and the steering oil pressure Pst from the steering oil pressure detecting means, for generating the exciting current which makes the displacement volume smaller as the value of (Pwk*Pst) becomes greater if (Pwk*Pst)>Pu holds good, and for inputting the exciting current into the auxiliary hydraulic pump.
6. A hydraulic circuit for a working vehicle in accordance with claim 1, where said variable displacement auxiliary hydraulic pump is an electromagnetic variable displacement auxiliary hydraulic pump in which the displacement volume is variable responsive to an exciting current;
further comprising:
an operating oil pressure detecting means for detecting operating oil pressure Pw of the working machine hydraulic circuit;
a steering oil pressure detecting means for detecting steering oil pressure Pst of the steering hydraulic circuit; and
a controller for storing a value of the predetermined oil pressure Pu, for receiving from the operating oil pressure detecting means a first signal representing the operating oil pressure Pw, for receiving from the steering oil pressure detecting means a second signal representing the steering oil pressure Pst, for generating the exciting current responsive to said first and second signals, and for inputting the exciting current into the auxiliary hydraulic pump.
7. A pump capacity control device comprising:
an engine;
a working machine hydraulic actuator;
a working machine hydraulic pump which is driven by said engine and which drives said working machine hydraulic actuator;
a working machine pump capacity control means for controlling working machine pump capacity, which is a discharge quantity for one rotation of said working machine hydraulic pump;
a working machine load detecting means; and
an engine speed detecting means;
wherein said working machine pump capacity control means reduces the working machine pump capacity as the working machine load is increasing, based on a detection value from the working machine load detecting means, and as the engine speed is decreasing, based on a detection value of the engine speed detecting means.
8. A pump capacity control device in accordance with claim 7, wherein said working machine pump capacity control means comprises:
a servo cylinder, for varying the displacement of said working machine hydraulic pump;
a control valve for operating said servo cylinder, said control valve having a first pilot pressure receiving surface and a second pilot pressure receiving surface;
first conduit means for supplying to said first pilot pressure receiving surface an operating oil pressure from said working machine pump; and
second conduit means for supplying to said second pilot pressure receiving surface a pressure which is representative of the detection value from the engine speed detecting means.
9. A pump capacity control device in accordance with claim 8, wherein said engine speed detecting means comprises:
an orifice;
a fixed displacement pump, which is driven by said engine, for discharging oil through said orifice;
a pressure relief valve connected to a downstream end of said orifice;
a pilot pressure control valve, which is actuated responsive to an upstream pressure of said orifice to connect said second pilot pressure receiving surface via said second conduit means to either a drain or a downstream pressure of said orifice.
10. A pump capacity control device comprising:
an engine;
a working machine hydraulic actuator;
a working machine hydraulic pump which is driven by said engine and which drives said working machine hydraulic actuator;
a working machine load detecting means;
a steering actuator;
a steering pump which is driven by the engine and which drives said steering actuator;
a steering pump capacity control means for controlling steering pump capacity, which is a discharge quantity for one rotation of the steering pump; and
a steering priority valve, for helpingly supplying pressurized oil, discharged from the steering pump, to the working machine actuator when the steering pump capacity is not less than an oil quantity which is necessary for the steering actuator;
wherein said steering pump capacity control means reduces the steering pump capacity as the working machine load is increasing, based on a detection value from the working machine load detecting means, and as the engine speed is decreasing, based on a detection value of the engine speed detecting means.
11. A pump capacity control device in accordance with claim 10, wherein the steering pump capacity control means controls the steering pump capacity so that the steering pump discharge does not exceed a predetermined value even if the engine speed is further increased, when the working machine load detecting means detects that the working machine load pressure is not more than a predetermined value and the steering pump discharge per unit time reaches a predetermined value as a result of an increase in the engine speed.
12. A pump capacity control device in accordance with claim 10, wherein said steering pump capacity control means comprises:
a servo cylinder, for varying the displacement of said steering pump;
a control valve for operating said servo cylinder, said control valve having a pressure receiving surface;
a load pressure sensor;
an engine speed sensor;
a proportional electromagnetic valve;
a control pump which supplies pressurized oil to said proportional electromagnetic valve;
conduit means for providing communication between said proportional electromagnetic valve and said pressure receiving surface;
a controller which receives a working machine load pressure value detected by said load pressure sensor and an engine speed value detected by said engine speed sensor, and which controls the proportional electromagnetic valve to connect said pressure receiving surface via said conduit means to either a drain or said control pump.