1. A method of transmitting and receiving pilots in a wireless multiple-input multiple-output (MIMO) communication system, comprising:
transmitting a MIMO pilot on a forward channel from a plurality of antennas and on a first communication link via a plurality of transmission channels, wherein the MIMO pilot comprises a plurality of pilot transmissions sent from the plurality of antennas, and wherein the pilot transmission from each antenna is configured to be identifiable by a communicating entity receiving the MIMO pilot; and
receiving a steered pilot on a reverse channel via a plurality of eigenmodes of a second communication link from the communicating entity, wherein at least some of the plurality of eigenmodes are used for data transmission, and wherein the steered pilot is generated based on the MIMO pilot and a channel response matrix for the plurality of transmission channels.
2. The method of claim 1, wherein the steered pilot comprises a specific set of modulation symbols that is subjected to spatial processing prior to transmission.
3. The method of claim 1, wherein the MIMO communication system supports one or more of a single-input multiple-output (SIMO) transmission mode, a diversity transmission mode, a beam-steering transmission mode, a beam-forming transmission mode, a non-steered spatial multiplexing transmission mode, a multi-user spatial multiplexing transmission mode, or a spatial multiplexing transmission mode.
4. The method of claim 1, wherein the pilot transmission from each antenna is associated with a different orthogonal code.
5. The method of claim 1, further comprising:
estimating a channel response of at least one eigenmode for the communicating entity based on the received steered pilot.
6. The method of claim 5, further comprising:
deriving a matched filter based on the estimated channel response of the at least one eigenmode, wherein the matched filter is used for matched filtering of a data transmission received via the at least one eigenmode from the communication entity.
7. The method of claim 1, wherein the steering pilot is transmitted at full transmit power from a plurality of antennas at the communicating entity.
8. An apparatus for transmitting and receiving pilots in a wireless multiple-input multiple-output (MIMO) communication system, comprising:
a transmit spatial processor operative to generate a MIMO pilot for transmission, on a forward channel, from a plurality of antennas and on a first communication link via a plurality of transmission channels, wherein the MIMO pilot comprises a plurality of pilot transmissions sent from the plurality of antennas, and wherein the pilot transmission from each antenna is configured to be identifiable by a communicating entity receiving the MIMO pilot; and
a receive spatial processor operative to process a steered pilot received on a reverse channel via a plurality of eigenmodes of a second communication link from the communicating entity, wherein at least some of the plurality of eigenmodes are used for data transmission, and wherein the steered pilot is generated based on the MIMO pilot and a channel response matrix for the plurality of transmission channels.
9. The apparatus of claim 8, wherein the steered pilot comprises a specific set of modulation symbols that is subjected to spatial processing prior to transmission.
10. The apparatus of claim 8, wherein the MIMO communication system supports one or more of a single-input multiple-output (SIMO) transmission mode, a diversity transmission mode, a beam-steering transmission mode, a beam-forming transmission mode, a non-steered spatial multiplexing transmission mode, a multi-user spatial multiplexing transmission mode, or a spatial multiplexing transmission mode.
11. The apparatus of claim 8, wherein the pilot transmission from each antenna is associated with a different orthogonal code.
12. The apparatus of claim 8, further comprising:
a controller operative to estimate a channel response of at least one eigenmode for the communicating entity based on the received steered pilot.
13. The apparatus of claim 12, wherein the controller is further operative to derive a matched filter based on the estimated channel response of the at least one eigenmode, wherein the matched filter is used for matched filtering of a data transmission received via the at least one eigenmode from the communication entity.
14. The apparatus of claim 8, wherein the steered pilot is transmitted at full transmit power from a plurality of antennas at the communicating entity.
15. A non-transitory computer-readable medium for use in a wireless multiple-input multiple-output (MIMO) communication system, having a set of instructions stored thereon, the set of instructions being executable by one or more processors to perform the steps of:
transmitting a MIMO pilot on a forward channel from a plurality of antennas and on a first communication link via a plurality of transmission channels, wherein the MIMO pilot comprises a plurality of pilot transmissions sent from the plurality of antennas, and wherein the pilot transmission from each antenna is configured to be identifiable by a communicating entity receiving the MIMO pilot; and
receiving a steered pilot on a reverse channel via a plurality of eigenmodes of a second communication link from the communicating entity, wherein at least some of the plurality of eigenmodes are used for data transmission, and wherein the steered pilot is generated based on the MIMO pilot and a channel response matrix for the plurality of transmission channels.
16. The computer-readable medium of claim 15, wherein the steered pilot comprises a specific set of modulation symbols that is subjected to spatial processing prior to transmission.
17. The computer-readable medium of claim 15, wherein the MIMO communication system supports one or more of a single-input multiple-output (SIMO) transmission mode, a diversity transmission mode, a beam-steering transmission mode, a beam-forming transmission mode, a non-steered spatial multiplexing transmission mode, a multi-user spatial multiplexing transmission mode, and a spatial multiplexing transmission mode.
18. The computer-readable medium of claim 15, wherein the pilot transmission from each antenna is associated with a different orthogonal code.
19. The computer-readable medium of claim 15, further comprising instructions for:
estimating a channel response of at least one eigenmode for the communicating entity based on the received steered pilot.
20. The computer-readable medium of claim 19, further comprising instructions for:
deriving a matched filter based on the estimated channel response of the at least one eigenmode, wherein the matched filter is used for matched filtering of a data transmission received via the at least one eigenmode from the communication entity.
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 circuit for preventing over-heat of heat-generating device comprising:
a heat-generating device, wherein one end of the heat-generating device is connected with a power source and another end of that is electrically connected to ground;
a heater circuit comprising a trigger circuit and a microprocessor, wherein the trigger circuit is connected with the power source and the heat-generating device and the microprocessor is connected with one end of the trigger circuit for controlling circuit conducting and heating the heat-generating device; and
a hot protecting circuit comprising a reactive trigger circuit, a resistor and a thermo fuse, wherein the thermo fuse is connected with one end of the heat-generating device; two ends of the resistor are connected with the reactive trigger circuit and the thermo fuse respectively; another end of the reactive trigger circuit is connected with the microprocessor such that once the microprocessor stops signals outputting, the power source, the thermo fuse and the resistor make a loop and the resistor is heated to ruin the thermo fuse for terminating heating.
2. The circuit as claimed in claim 1, wherein the trigger circuit of the heater circuit comprises a capacitor, a resistor and a second switch connecting in series.
3. The circuit as claimed as in claim 2, wherein the second switch is a bidirectional thyristor (TRIAC).
4. The circuit as claimed in claim 2, wherein one end of the second switch is electrically connected to ground and another end of that is connected with the heat-generating device and the microprocessor; the second switch is connected with two resistors in parallel.
5. The circuit as claimed in claim 4, wherein the microprocessor stops outputting signals to the hot protection circuit when the second switch is short-circuited.
6. The circuit as claimed in claim 1, wherein the microprocessor stops outputting signals to the hot protection circuit when it is damaged.
7. The circuit as claimed in claim 1, wherein the reactive trigger circuit comprises a first, a second and a third NPN bipolar transistors that are connected each other; a first and a second resistor-capacitor (RC) circuits are connected with the bases of the first and the second NPN bipolar transistors respectively; the first resistor-capacitor (RC) circuit is connected with the microprocessor and the emitters of the three NPN bipolar transistors are electrically connected to ground; the collectors of the three NPN bipolar transistors are connected with the rectified power source; a first switch is connected with the collector of the third NPN bipolar transistor and a resistor of the hot protection circuit respectively.
8. The circuit as claimed in claim 7, wherein the first switch is a bidirectional thyristor (TRIAC).
9. The circuit as claimed in claim 7, wherein one end of the first switch is connected with two resistors in parallel; the two resistors are connected with the microprocessor and another end of the first switch is connected with a resistor of the hot protection circuit.
10. A method for preventing over-heat of heat-generating device comprises following steps:
a. providing a heat-generating device wherein one end of the heat-generating device is connected with a power source and another end of that is electrically connected to ground; and a heater circuit comprising a trigger circuit and a microprocessor; the trigger circuit is connected with the power source and the heat-generating device; the microprocessor is connected with one end of the trigger circuit for controlling circuit conducting and heating the heat-generating device; and
b. providing a hot protection circuit comprising a reactive trigger circuit, a resistor and a thermo fuse; the thermo fuse is connected with one end of the heat-generating device; two ends of the resistor are respectively connected with the reactive trigger circuit and the thermo fuse; another end of the reactive trigger circuit is connected with the microprocessor such that once the microprocessor stops outputting signals, the power source, the thermo fuse and the resistor make a loop and the resistor is heated to ruin the thermo fuse for terminating heating.
11. The method as claimed as in claim 10, wherein the trigger circuit of the heater circuit comprises a capacitor, a resistor and a second switch connecting in series.
12. The method as claimed in claim 10, further comprising a step of detecting by a second switch such that the microprocessor stops outputting controlling pulse to the second switch of the trigger circuit of the heater circuit, by the response of the heater circuit, the trigger circuit is known whether to be in normal condition or not and the microprocessor determines whether to terminate heating.
13. The method as claimed in claim 10, wherein the reactive trigger circuit comprises a first, a second and a third NPN bipolar transistors that are connected each other; a first and a second resistor-capacitor (RC) circuit are respectively connected with the bases of the first and the second NPN bipolar transistors, the first resistor-capacitor (RC) circuit is connected with the microprocessor and the emitters of the three NPN bipolar transistors are electrically connected to ground; the collectors of the three NPN bipolar transistors are connected with the rectified power source; a first switch is connected with the collector of the third NPN bipolar transistor and a resistor of the hot protection circuit respectively.
14. The method as claimed in claim 13, wherein one end of the first switch is respectively connected with the microprocessor and a resistor of the hot protection circuit.
15. The method as claimed in claim 14, further comprising a step of detecting by a first switch such that the microprocessor stops outputting controlling pulse to the reactive trigger circuit and the second switch, by the response of the path between the first switch and the microprocessor the first switch is known whether to be in normal condition or not and the microprocessor determines whether to terminate heating.
16. The method as claimed in claim 10, wherein the microprocessor stops outputting signals to the hot protection circuit when it is damaged.