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Quiz Sketch the time domain waveform and spectrum, labeling all important features, of a rectangular pulse of 2.4 Ghz having 1 uS duration. Bluetooth. Operation in the Industrial/Scientific/Medical (ISM) band @ 2.4 Ghz “Low power, uncoordinated, interference dominated RF environment”.
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Quiz Sketch the time domain waveform and spectrum, labeling all important features, of a rectangular pulse of 2.4 Ghz having 1 uS duration.
Bluetooth Operation in the Industrial/Scientific/Medical (ISM) band @ 2.4 Ghz “Low power, uncoordinated, interference dominated RF environment” • Pico-Net architecture • One master • Up to seven active slaves • Up to 200 inactive (parked) slaves • Devices may participate in multiple pico-nets (scatternet) • Master in one pico-net may be slave in another • Transmit Power • Class-1: 100 mW • Class-2: 0.25 to 2.5 mW • Class-3: 1 mW • 10 m range for Rx sensitivity of -70 dBm, 10-3 BER
Modulation • Gaussian Filtered 2FSK +/- 175 kHz deviation@ 1 M-symbol/sec (1bit/symbol) • Frequency Hopping at 1600 hops/sec • 625 uS “Hop slot” • 366 uS per slot available for one data packet • Masters transmit in even numbered slots • Addressed slaves transmit in next odd slot • Packets may be extended to three or five slots • Five different hopping sequences • 79 One-Mhz channels between 2400 – 2483.5 Mhz • Maximum throughput is 721/57.6 or 432.6/432.6 kb/s Synchronous Connection Oriented (SOC) protocol – voice Asynchronous, connectionless (ACL) protocol – packet data • Error Correction: • 1/3 rate FEC • 2/3 rate FEC • ARQ
Packet Types • System Packets: • NULL, POLL, FHS • Medium Rate error-protected(2/3 rate FEC) • DM1, DM3, DM5 • High Rate Unprotected (No FEC in Payload) • DH1, DH3, DH5 • Digitized Audio, 3 levels of error protection • HV1, HV2, HV3 • Mixed data/voice • DV • Other • AUX
Packet Structure 0 to 2745 bits 72 bits 54 bits Access Code Header Payload + CRC(16 bit) 4 bits 64 bits 4 bits Access Code Preamble Sync word + BT-Addr Trailer 3 bits 4 bits 1 bit 1 bit 1 bit 8 bits Header Type Flow ARQ AM-Addr Seq CRC
Addressing • BT-Addr : • Bluetooth identifier, unique to each registered bluetooth type device: 48 bits /1014 possible • AM-Addr: • 1-7 for each Active Member slave; 0 broadcast to all • PM-Addr: • 8 bit Parked Member address assigned before parking device
Link Synchronization • ACL – Asynchronous connection link • Used for Data, • Error detection/ARQ • SCO-Synchronous Connection Oriented • Used for voice or other real-time data • Reserved transmission slots • FEC – no retransmission
Wi-Fi(Wireless Fidelity) • Extension to IEEE 802.11b in 1999 by WECA (Wireless Ethernet Compatibility Alliance) • Operation in ISM band with data rates of 5.5 and 11 Mbits/sec (nominal) ,1 and 2 Mb/s fallback rates • Direct sequence modulation • Complimentary Code Keying (CCK) • Packet Binary Convolutional Coding (PBCC) • Assigned 22 Mhz region in ISM band, overlapping Bluetooth – so bluetooth is required to “hop over” this band if Wi-Fi is detected. • 802.11a also defines assignments in the UNII (Unlicensed National Information Infrastructure) band at 5 Ghz. • 6 Mb/s to 54 Mb/s using OFDM (Orthogonal Frequency-Division Modulation)