Speech codecs for high-quality voice over ZigBee applications: Evaluation and implementation challenges

Evaluation of narrow band speech codecs for Ubiquitous Speech Collection and Analysis Systems

“…A few works have tried to analyze the key factors which influence the high quality voice transmission in adhoc-devices [6]. Some of these factors are also valid in evaluating low bit rate codecs and this work tries to evaluate those selected codecs in noise perspective along with some of those related basic factors.…”

HD2UB: A voice communication system for underground mine monitoring

“…In the design of voice node, Crossbow developed TMTS300CA and MTS310CA, such two sensor nodes with integrated light, temperature, voice, buzzer and magnetometer acquisition node in order to connect Mica, MicaZ sensor nodes series [8]. With an adaptive noise cancellation method, Cao et al proposed a voice communication system which reduces noise in communication, including the FPGA chip for PCM voice collection and the TMS320 VC5402 components for speech enhancement [9].…”

A-LNT: A Wireless Sensor Network Platform for Low-Power Real-Time Voice Communications

“…There are a few suitable protocols and platforms for WASNs (wireless audio sensor networks) [9] at present [10][11][12][13][14]. Gabale et al present a TDMA-(time division multiple access-) based MAC protocol LiT [10] and implement the MAC on an 802.15.4 platform Tmote; the evaluation of LiT shows quick flow setup, low packet delay, and essentiality for real-time applications; however, the speech coder chosen is G.723.1, and the coding bit is 6.3 kbps, but the speech codec power consumption is not considered; in 2012, a Lo 3 system based on LiT was reported [15], and it showed that such system bodes well with cost and power constraints in rural regions; the audio codec is SPEEX [16] with data rate of 5.9 Kbps, and the expected lifetime is 5 days.…”

“…Li et al study the audio element detection method in audio sensor network [11], and audio is treated as a special sensing data. In [12], speech codecs for high-quality voice over ZigBee applications are discussed. Zhao et al design and implement an enhanced surveillance platform with low-power WASN; three kinds of audio sensors are discussed [13].…”

“…Check RF channel (4) if RF channel is not available (5) If RF channel == MAX RF CHANNEL (6) Halt application. 7else (8) RF channel +1; (9) continue; (10) else (11) break; (12) while (1) (13) Sleep; (14) Wake up for RF packet receiving or system event (15) if time == T SENDING SYNC // time for sending synchronization (16) Send POLL(ALL NODES); (17) else if received RF packet (18) Unpack the packet, extract source address NODEA; (19) If packet type == ACK POLL (20) if the node is synchronized (21) TOUT NODE = 0; // clear timeout counter of the node (22) else if packet type == ACK POLL DATA (23) if the node is synchronized (24) TOUT NODE = 0; Listen to radio channel for 100 ms (5) if RF packet received (6) Calculate system time 7Set system parameter; (8) while (counter < CMAX) (9) Send APPLY(CNODE) (10) while ( < TTIMEOUT) (11) Listen to radio channel (12) if ACK APL received (13) break; (14) else if DENY received (15) break; (16) if ( ≥ TTIMEOUT) (17) counter++; (18) else if DENY received (19) RF channel = unavailable; (20) break; (21) else if ACK APL received (22) counter = 0; In our design, the work is mainly done by CNODE. It chooses an available radio channel and waits for radio packet receiving events.…”