CSR蓝牙固件关于对信号强度RSSI的应用HCI Implementation (bcore-an-032Pa).doc

6.51 (HCI: 7.5.3) Read_Link_Quality6.51（HCI：7.5.3）Read_Link_QualityThis command obtains a value in the range 0 to 0xff, describing the quality of an ACL connection.此命令获得一个说明ACL连接质量的值，其介于0至0xff之间。The values meaning is manufacturer-specific.这个值的意思是制造商特定的。The value is derived from an averaged bit error rate (BER) measurement, updated as packets are received.该值是源于平均误码率（BER）的测量，接收数据包时更新。The BER value is derived from parts of radio packets that support FEC error correction:误码率是来自部分无线数据包，支持FEC的错误： All packets headers 所有数据包的包头 The payloads of DM1, DM3, DM5, HV1 and HV2 packetsDM1，DM3，DM5，HV1和HV2包的有效载荷 The data parts of DV packetsDV包的数据部分The technique used to derive BER values is not precise; it is intended only to give an indication of link quality rather than act as a precise, calibrated instrument.该手法用于计算误码率的值是不准确的，它只是为了指示链路的质量，而不是作为一个精确的测量指示。Links BER values are used internally to adapt to changes in link quality, notably to support CQDDR (Channel Quality Driven Data Rate).链路的误码率值是在内部使用，以适应变化的高质量链接，特别是支持CQDDR（根据信道质量确定数据速率）。The HCI commands values are as follows.HCI命令的值如下。 Between 0xff and 0xd7 each bit distance represents 0.0025% BER. Thus: 在0xff和0xd7间的每个位代表0.0025的误码率。因此： Between 0xd6 and 0x5a each bit distance represents 0.08% BER. Thus:在0xd6和0x5a间的每个位代表误码率0.08。因此： Between 0x59 and 0x00 each bit distance represents 0.64% BER.在0x59和0x00间的每个位代表误码率0.64。As a rule of thumb, a link with a BER between 0 and 0.1% is workable. 根据经验，链路的误码率在0和0.1%之间是可行的。Trying to run a link with a BER above 1% gives poor results. 尝试运行一个误码率大于1%的连接会给出差的结果。Note: 注意：For EDR links these tables are not valid. It is not possible to convert link quality into BER.这些表对于EDR链路无效。它不可能转化为链路质量的误码率。6.52 (HCI: 7.5.4) Read_RSSI 6.52（HCI：7.5.4）Read_RSSI A common user hope is to use this commands return values as the basis of a general-purpose signal strength meter. 通常用户希望使用此命令返回基于多方信号强度计量的值。Unfortunately, the command, as specified by BT1.1, is almost useless for this role. 不幸的是，这个命令，由BT1.1指定，这个角色几乎是无用的。 While a links received signal strength is within the Golden Receive Power Range the command returns an RSSI value of zero. 在链路处于黄金接收功率范围内时，此命令返回一个零的RSSI值。 The Golden Receive Power Range is normally around 20dBm wide, crudely equating to a physical range factor of ten. (For example, between 1m and 10m the RSSI value could be zero.)黄金接收功率范围是通常在20dBm宽度周围，粗略的等同于10的物理范围。（例如，1米和10米之间的RSSI的值都可以是零。） The RSSI value only goes positive or negative when the received signal slips outside the Golden Range. RSSI的值仅仅是变正或负，当收到的信号在黄金范围外时。 Where dynamic power control is available, the firmwares LM emits LMP_incr_power_req or LMP_decr_power_req messages to the Bluetooth peer to try to bring the received signal strength back into the Golden Range. 当动态功率控制是可用的，固件的LM发出LMP_incr_power_req或LMP_decr_power_req消息给蓝牙匹配尝试把接收到的信号强度调回黄金范围。BT1.1 requires only that the function return a negative value when the RSSI is below the Golden Range, zero within it, and a positive value when the RSSI is above the Golden Range. BT1.1只要求函数在低于黄金范围时返回一个负的RSSI，零也在其中，高于黄金范围时返回一个正的RSSI。 When the RSSI is above the Golden Range, the firmware returns a positive number. 当RSSI高于黄金范围时，固件返回一个正数。 The value is an approximation of the dB between the top of the Golden Range and the RSSI. 该值是一个近似的dB，在黄金范围的顶部和RSSI之间。The value is very crude: it can be 5dB from the real value, there is no guarantee that a constant RSSI will give a constant return value, and thus there is no guarantee that the mapping from RSSI to the returned value will be monotonic. 该值是很简陋：它可以与真实的值相差5dB，但不能保证一个恒定不变的RSSI将返回一个恒定不变的值，所以是不能保证从RSSI的映射到返回的值将是单调的。 When the RSSI is within the Golden Range, the firmware returns zero. 当 RSSI在黄金范围内时，固件返回零。 When the RSSI is below the Golden Range, the firmware returns a negative number. 当RSSI低于黄金范围时，固件返回一个负数。 The value is an approximation of the dB between the RSSI and the bottom of the Golden Range. 该值是一个近似的dB，在黄金范围的底部和RSSI之间。The value is even more crude than for positive values: it can be more than 5dB from the real value, there is no guarantee that a constant RSSI will give a constant return value, thus there is no guarantee that the mapping from RSSI to the returned value will be monotonic, and the value clips at a minimum of approximately -10dB. 该值甚至比正值更粗糙：它可以与真实的值差5dB，但不能保证一个恒定不变的RSSI将返回一个恒定不变的值，因此也不能保证，从返回的映射的RSSI值将是单调的，并在约- 10dB的最低值剪辑。 The firmware therefore supports the bare minimum required by BT1.1. 因此，该固件支持的最低限度为BT1.1。 This is not useful for a general-purpose power meter. 这不是一个有用的通用功率计。 Behaviour for HCIStack1.2v19.2 and Later Builds HCIStack1.2v19.2及其后续构建的行为On HCIStack1.2v19.2 and later builds the accuracy of the value returned by HCI_Read_RSSI has been improved. 在HCIStack1.2v19.2及其以后构建的程序中，HCI_Read_RSSI的返回值准确性已有所改善。 In addition, reading BCCMD command RSSI_ACL retrieves an indication of the RSSI for the given ACL handle (rather than how far above or below the golden range the RSSI is, as HCI_Read_RSSI does). 此外，阅读BCCMD命令RSSI_ACL为给定的ACL检索RSSI的指示（而不是远远高于或低于RRSI的黄金范围，正如HCI_Read_RSSI一样）。The value returned should be interpreted as a signed twos-complement (16 bit) integer. The value returned is always negative because the reading saturates at about -20 dBm.返回值应解释为一个有符号整数的补码（16位）。返回值始终是负的，因为阅读的饱和约-20dBm。BCCMD RSSI_ACL returns OK if a signal strength can be supplied, and ERROR if the handle is no longer valid. 如果信号强度可以提供，那么BCCMD RSSI_ACL返回正确，否则返回错误句柄不再正确。 The signal strength returned is zero when the chip returns the ERROR status. The value returned is a rolling average and responds more slowly to changes when the data is transmitted less frequently. 当芯片返回的状态为错误时，RSSI返回值为0。该值返回是平均滚动的，在数据传输不频繁的时候，其改变的也慢。 Note: 注意：The accuracy of the result is likely to be within +/- 4dBm. 结果准确性的可能是在+ / - 4dBm。However, this measurement is not calibrated or tested on a per-chip basis and CSR makes no warranty about its accuracy.然而，RSSI的测量不是校验或测试每个芯片的基准，CSR对其准确性不作任何保证。Users should establish for themselves whether this meets their requirements across a range of devices. 用户应自己建立能满足其需求的命令。6.37 (HCI: 7.3.37) Read_Transmit_Power_LevelWhen used to o