Packet acquisition and channel tracking for a wireless communication device configured in a zero intermediate frequency architecture
First Claim
1. A method of controlling operation of a wireless communication device configured in a zero intermediate frequency (ZIF) architecture including a DC feedback control loop and a gain feedback control loop, the method comprising:
- processing energy in a wireless medium to generate a corresponding receive signal;
monitoring the receive signal via a predetermined measurement window;
detecting a changed condition in the wireless medium;
holding the gain feedback control loop at a constant gain level after detecting the changed condition; and
operating the DC feedback control loop in an attempt to search a stable DC value for the receive signal while the gain feedback control loop is held at the constant gain level.
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Accused Products
Abstract
A method of controlling operation of a wireless device configured in a zero intermediate frequency architecture including a DC loop and a gain loop. The method includes processing energy in a wireless medium to generate a corresponding receive signal, monitoring the receive signal via a predetermined measurement window, detecting a changed condition in the channel, holding the gain feedback control loop at a constant gain level, and operating the DC loop in an attempt to search a stable DC value for the receive signal while the gain loop is held constant. A first case is DC saturation, where the gain is held constant until DC is controlled. A second case is clear channel assessment, where a prior stored gain setting is applied to the gain loop after detecting the end of the packet. A third case is preparation for receiving an expected acknowledgement packet after transmitting a packet, where again a prior stored gain setting is applied to the gain loop and DC is searched.
75 Citations
60 Claims
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1. A method of controlling operation of a wireless communication device configured in a zero intermediate frequency (ZIF) architecture including a DC feedback control loop and a gain feedback control loop, the method comprising:
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processing energy in a wireless medium to generate a corresponding receive signal; monitoring the receive signal via a predetermined measurement window; detecting a changed condition in the wireless medium; holding the gain feedback control loop at a constant gain level after detecting the changed condition; and operating the DC feedback control loop in an attempt to search a stable DC value for the receive signal while the gain feedback control loop is held at the constant gain level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of operating a wireless communication device to perform initial acquisition of a packet being transmitted in a wireless medium, the wireless communication device configured in a zero intermediate frequency (ZIF) architecture including a DC feedback control loop and a gain feedback control loop, said the method comprising:
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processing radio frequency (RF) energy in the wireless medium to generate a corresponding receive signal; determining if a DC threshold condition of the receive signal is exceeded; if the DC threshold condition is exceeded, holding the gain feedback control loop at a constant gain level and operating the DC feedback control loop to reduce DC of the receive signal until the DC threshold condition of the receive signal is met; and when the DC threshold condition of the receive signal is met, operating the DC feedback control loop to control the DC level of the receive signal and operating the gain feedback control loop to control a power level of the receive signal to a predetermined target power level. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method of operating a wireless transceiver device in preparation for an expected acknowledgment packet, the wireless transceiver device configured in a zero intermediate frequency (ZIF) architecture and including a DC feedback control loop and a gain feedback control loop, the method comprising:
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holding a gain level of the gain feedback control loop constant during a predetermined quiet period after transmission of a packet; operating the DC feedback control loop during the predetermined quiet period in an attempt to resolve DC level while the gain feedback control loop is held constant; and after the quiet period, releasing the gain feedback control loop to operate in a normal packet acquisition mode. - View Dependent Claims (23, 24)
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25. A method of operating a wireless communication device to determine clear channel assessment of a wireless medium, the wireless communication device configured in a zero intermediate frequency (ZIF) architecture and including a DC feedback control loop and a gain feedback control loop, the method of comprising:
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storing a gain level value of the gain feedback control loop; detecting a packet being transmitted; after transmission of the packet is completed, retrieving the stored gain level value and holding the gain feedback control loop at the retrieved gain level value; operating the DC feedback control loop to search a stable DC level; and determining whether the DC loop converges to a stable DC level. - View Dependent Claims (26, 27, 28, 29, 30)
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31. An apparatus for controlling DC offset voltage comprising:
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an automatic gain control (AGC) amplifier having a gain control input configured to set a gain of the AGC amplifier; a gain feedback control loop connected to the gain control input configured to set the gain of the AGC amplifier, wherein the gain feedback control loop is configured to detect a changed condition in a wireless medium and to responsively hold the gain of the AGC amplifier constant; a DC feedback control loop configured to generate a DC offset correction signal to reduce a DC offset voltage while the gain feedback control loop is held constant. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39, 40)
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41. An apparatus for controlling DC offset voltage comprising:
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an automatic gain control (AGC) amplifier; an AGC gain signal generator connected to the AGC amplifier; a DC offset signal generator configured to generate a DC offset correction signal, compensation logic circuitry connected to the AGC gain signal generator and the DC offset signal generator, and configured to detect a changed condition in a wireless medium and to responsively hold the gain of the AGC amplifier constant while controlling the DC offset signal generator to reduce a DC offset. - View Dependent Claims (42, 43)
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44. An apparatus comprising:
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a zero intermediate frequency (ZIF) transceiver; and a baseband processor configured to detect a changed condition in the wireless medium, wherein the baseband processor further comprises; a gain feedback control loop configured to maintain a constant gain level after detection of the changed condition; and a DC feedback control loop configured to search for a stable DC value for the receive signal while the gain feedback control loop is maintained at the constant gain level. - View Dependent Claims (45, 46, 47, 48, 49)
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50. An apparatus comprising:
a processor configured to determine if a DC threshold condition of a receive signal is exceeded;
wherein the processor further comprises;a gain feedback control loop configured to maintain a constant gain level in response to a determination that the DC threshold condition of the receive signal is exceeded and control a power level of the receive signal at a predetermined target power level in response to a determination that the DC threshold condition of the receive signal is not exceeded; and a DC feedback control loop configured to reduce a direct current level of the receive signal until the DC threshold condition of the receive signal is met in response to the determination that the DC threshold condition of the receive signal is exceeded and control the direct current level of the receive signal in response to the determination that the DC threshold condition of the receive signal is not exceeded. - View Dependent Claims (51, 52, 53, 54, 55, 56)
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57. An apparatus comprising:
a processor including; a gain feedback control loop configured to maintain a gain level constant during a predetermined quiet period after transmission of a packet and operate in a normal packet acquisition mode after the quiet period; and a DC feedback control loop configured to resolve a direct current level while the gain feedback control loop maintains the constant gain level. - View Dependent Claims (58, 59, 60)
Specification