Methods and apparatuses for channel assessment

An apparatus for channel assessment, comprising:

• a radio frequency (RF) unit;
• a baseband unit coupling to the RF unit, and directing the RF unit to selectively hop into one of a plurality of available channels in a frequency band using a pseudorandom sequence to receive a plurality of packets via the hopped channel;
• and
• a microprocessor control unit (MCU) coupling to the baseband unit, accumulating a measure for the hopped channel according to reception results of the packets, and marking the hopped channel as a bad channel when the accumulated measure exceeds a predetermined threshold, where during packet reception via the hopped channel, the MCU increases the measure by a predefined first value when a packet is lost, increases the measure by a predefined second value smaller than the predefined first value when a received packet header does not pass error check, and increases the measure by a bit error count representing a quantity of bits have been corrected when a received packet header passes error check, the MCU further canceling a bad mark for a re-activation channel other than the hopped channel, wherein any channel without a bad mark can be hopped, and the re-activation channel is a betweenness channel between the hopped channel and a higher frequency channel g1 without a bad mark, or between the hopped channel and a lower frequency channel g2 without a bad mark;
• wherein the measure represents the inaccuracy extent of a plurality of packet headers during packet reception via the hopped channel.