物联网与短距离无线通信技术第二章技术分析.ppt

* * * * SCO面向同步连接：主要用来传输语音，速率为64kbps。主从单元点对点的连接。 ACL异步无连接：主要传输数据，非对称连接速率为721/57.6kbps。对称传输为342.6kbps。微微网内主单元和全部从单元之间点对多点的链路。 * * * * * * Ask some questions. * * 拨号网络，用作Internet网桥 * * * * 工作在park模式下的设备放弃了mac地址，偶尔收听master的消息并恢复同步、检查广播消息。如果我们把这几 种工作模式按照节能效率以升序排一队，那么依次是：呼吸模式、保持模式和暂停模式。 * * * * (1)无线电(radio)：确定包括频率、跳频的使用、调制模式和传输功率在内的空中接口细节。 (2)基带(baseband)：考虑一个微微网中的连接建立、寻址、分组格式、计时和功率控制，实现微微网的建立。 (3)链路管理器协议(link manager protocol，LMP)：负责蓝牙各设备间连接的建立和设置。LMP通过连接的发起，交换和核实进行身份认证和加密，通过协商确定基带数据分组大小；还控制无线设备的节能模式和工作周期，以及微微网络内设备单元的连接状态。 (4)逻辑链路控制和自适应协议(logical link control and adaptation protocol，L2CAP)：使高层协议适应基带层。L2CAP提供无连接和面向连接服务。 (5)服务发现协议(service discovery protocol，SDP)：询问设备信息、服务与服务特征，使得在两个或多个蓝牙设备间建立连接成为可能。 * * Paging 寻呼 * * ? ?Parked units：暂停单元，即piconet中与网络保持同步但没有Mac address的设备。 The three-octet OUI can be used to generate Universal LAN MAC addresses and Protocol Identifiers per ANSI/IEEE Std 802 for use in Local and Metropolitan Area Network applications. * * 目的 同步 DC offset compensation Identification Signaling * * 使用码率为1/3的FEC编码得到54位头部 * * Link Controller The link controller is responsible for the encoding and decoding of Bluetooth packets from the data payload and parameters related to the physical channel, logical transport and logical link. The link controller carries out the link control protocol signaling (in close conjunction with the scheduling function of the resource manager), which is used to communicate flow control and acknowledgement and retransmission request signals. The interpretation of these signals is a characteristic of the logical transport associated with the baseband packet. Interpretation and control of the link control signaling is normally associated with the resource manager’s scheduler. * * Link Manager The link manager is responsible for the creation, modification, and release of logical links (and, if required, their associated logical transports), as well as the update of parameters related to physical links between devices. The lin