摘要:
Disclosed are methods and systems for state switching. The method is applied to a first hardware system. The first hardware system is connected with a second hardware system. The first hardware system has a first operation state and a second operation state. The second hardware system includes a memory unit. The memory unit has a first access state and a second access state. The memory unit is in the first access state currently. The method includes: the first hardware system sends an access state switching instruction to the second hardware system when the first hardware system enters the second operation state from the first operation state, wherein, the access state switching instruction is adapted to switch the memory unit of the second hardware system from the first access state to the second access state. The application of the present invention can ensure the security of key data, avoid the access of key data by malicious software, reduce the implementation costs and has a higher extensibility.
摘要:
Methods and apparatus are provided for communicating data in a multiple antenna communication system having N transmit antennas. According to one aspect of the invention, a header format includes a legacy preamble having at least one legacy long training field and an extended portion having at least N additional long training fields on each of the N transmit antennas. The N additional long training fields may be tone interleaved across the N transmit antennas and are used for MIMO channel estimation. The extended portion may include a short training field for power estimation. The short training field may be tone interleaved across the N transmit antennas and have an extended duration to support beam steering.
摘要:
Electronic devices may be provided that contain wireless communication circuitry. The wireless communication circuitry may include radio-frequency transceiver circuitry coupled to antennas. An electronic device may include a baseband processor and other storage and processing circuitry that implements protocol stacks for handling multiple radio access technologies. The storage and processing circuitry may use the transceiver circuitry to convey data using a first radio access technology while periodically interrupting the conveying of the data to monitor a paging channel using a second radio access technology. In performing the paging channel monitoring operations, the storage and processing circuitry may enforce a time limit that ensures that operations using the first radio access technology are not disrupted more than desired.
摘要:
Electronic devices may be provided that contain wireless communications circuitry. The wireless communications circuitry may include radio-frequency transceiver circuitry coupled to multiple antennas. An electronic device may alternate between a sleep mode and a wake mode. During wake mode, the electronic device may monitor a paging channel in a wireless network for incoming paging signals. The device may use either a single antenna mode or a multiple antenna mode such as a dual antenna mode in monitoring the paging channel. In the single antenna mode, a single active antenna is used to receive paging signals. In the dual antenna mode two antennas are simultaneously used to receive paging signals. The device may choose which antenna mode to use based on signal quality measurements and history information on successfully received paging signals.
摘要:
A method and apparatus are disclosed for transmitting symbols in a multiple antenna communication system. The disclosed frame structure comprises a preamble having a plurality of long training symbols that are transmitted on a plurality transmit antennas. At least a portion of the frame is delayed on at least one transmit antenna. The disclosed frame formats of the present invention are backwards compatible to existing single antenna communication systems. The delay amount, D, can be approximately equal to one OFDM time sample period, T. The delayed version can be obtained by introducing a time delay into a signal on the delayed branch(es) or by cyclically shifting at least a portion of each frame on the delayed branch(es). The entire frame or only the preamble portion of each frame can be delayed.
摘要:
A Channel Quality Indicator table for wireless multiple input multiple output (MIMO) networks is disclosed. In one embodiment, a method of generating a table for channel quality indicator (CQI) for an open loop MIMO transmission includes calculating performance of a link between a transmitter and a user end unit for each MIMO transmission mode over a range of average signal-to-noise ratio, and selecting the MIMO transmission mode that maximizes performance for each subset of the range of average signal-to-noise ratio. The method further includes storing the selected MIMO transmission mode and the corresponding subset of the range of average signal-to-noise ratio in a CQI table, the CQI table being stored in an user end unit and a base transceiver station of the open loop MIMO network.
摘要:
In one embodiment, a timing-offset estimator calculates a correlation value for each sample of an OFDM signal having a cyclic prefix for each OFDM symbol. The correlation value is provided to a tapped delay line that applies a separate weight to each of 2V correlation values, where V is the length of the cyclic prefix and the weights are based on a triangular weighting scheme that increases linearly from the first value, peaks at the Vth value, and decreases linearly to the 2Vth value. A stream of combined, squared correlation values is generated by combining and squaring the 2V weighted correlation values for each sample of the OFDM signal. For each cyclic prefix of the OFDM signal, a timing-offset estimate is determined based on a detected peak value in the stream of combined, squared correlation values. A timing-offset estimator with triangular weighting scheme may be implemented using recursive processing.
摘要:
A mobile wireless device adapts transmit power levels and number of retransmissions of a preamble sent to a wireless network. The mobile wireless device measures characteristics of a downlink signal received from the wireless network. The mobile wireless device transmits a series of preambles to the wireless network, each successive preamble having an increased power level, starting at a power level based on the measured received signal characteristics and on parameters received from the wireless network, up to a maximum transmit power level. When the transmit power level of the preamble exceeds the maximum transmit power level and when the measured downlink signal quality falls below a threshold, the mobile wireless device limits the number of preamble retransmission to less than an allowed maximum number of retransmissions. A minimum number of retransmissions is determined and adapted to higher values for larger measured values of downlink signal quality.
摘要:
Managing radio resources across dual networks includes a wireless mobile device connecting to a first wireless network using a first radio access technology. The wireless device may notify the first network of a capability to be temporarily non-responsive to the first network while maintaining a signaling connection to the first network. The wireless device may communicate with a second network. The wireless device may return to communicating with the first network subsequent to communicating with the second network, and in response to communicating with the second network for less than a predetermined amount of time, the wireless device may send a scheduling request to the first network. In response to receiving a grant acknowledgement from the first network, the wireless device may send a buffer status report that includes a value such as zero to indicate that the wireless device has returned to and can communicate with the first network.
摘要:
Electronic devices may be provided that contain wireless communication circuitry. The wireless communication circuitry may include radio-frequency transceiver circuitry coupled to first and second antennas. An electronic device may send network access probe signals to a base station in a wireless network. If the base station responds with a corresponding acknowledgement, the electronic device and base station may establish a wireless communication link such as a cellular telephone link. In response to failure to receive the acknowledgement signal from the base station, the electronic device may increase the transmit power of a successive network access probe signal. The electronic device may switch between use of the first and second antennas when transmitting the network access probe signals. The electronic device may alternate between the first and second antennas or may use other antenna usage patterns.