MCMP:Multichannel Multi Point Voice Communication in NFMI Hearing Aid

Transcription

1 MCMP:Multichannel Multi Point Voice Communication in NFMI Hearing Aid Senthilmurugan.S 1, Dept of Computer science and Engineering MVJ College of Engineering Bangalore , India Mrs.Rajapuspha T 2, Associate. Prof, Dept of Computer science and Engg, (PG) MVJ College of Engineering Bangalore , India puspha.rambabu@gmail.com Abstract Wireless technology is widespread in our society. During the course of my research when designing wireless hearing instrument line, there are many types and methodologies used for wireless transmission. This paper summarizes the advanced binaural processing technology helps to feed the information that reflects the natural world as closely as possible using multi point multi channel communication in NFMI. More recently, hearing instruments have become available that use digital wireless transmission, either to exchange information between right and left devices or to receive information from another source, such as a television or telephone. An issue with NFMI streaming is that there is a one to one relationship between audio sources and the body worn streamer. This means that a married couple wearing hearing instruments with the same wireless capabilities would not be able to share streaming devices in their home; two separate streaming devices connected to the television would be required, as would two streaming devices connected to the telephone. Thus the user requirement to connect to multiple audio devices and for users to share connections is not met. We proposed the optimal solution for with NFMI to carefully consider both user needs and feasibility of implementing the technology. Keywords-component; MCMP, NFMI, Binaural Processing Technology. I. INTRODUCTION Hearing aids have always been designed as stand-alone, miniaturized amplification devices. The strategy as to what sort of amplification characteristics should be included has been based on measures of threshold hearing loss and disruptions in loudness dynamics in each ear separately. However, our [2] auditory system is truly a system that relies on inputs from two different sensors (right and left ears) and a central processor (the brain). Amplification has rarely included considerations of how this system works, especially in terms of the relationships between the signals that enter the system via the two different ears. Miniaturization of the technology providing for wireless transmission of signals has now opened the possibility that hearing aids can have radio transmitters and receivers on board. One use of these technologies is to transmit signals from outside audio sources to the hearing aids. The other major use of wireless technology in hearing aids is to have the two devices in a bilateral fitting communicate with each other. [2] The brain relies on information that is supplied by the two separate ears. Sometimes the signal of interest is in one ear and not the other, for example while listening on the phone. However, it is more common that auditory signals are present in both ears, but not necessarily in exactly the same form. Synchronized differences between the two ears provide crucial information as to where the sounds come from. Being able to assign location to all of the sounds in the environment is the first step in separating the signal of interest (especially speech) from background competition. Preservation of ear-to-ear differences is essential in amplification in order to provide the brain with all of the information that it needs. First, wireless technology in today s hearing aids can be classified into one of three types: [3] near-field magnetic induction (NFMI), 900 MHz, or 2.4 GHz. These three technologies span wide wireless frequency range. NFMI uses the lowest range of frequencies and will be referred to as near-field wireless communication [1]. The NFMI wireless signal easily passes through and around objects such as the human head, making it a favorable option for ear-to-ear signal processing. The disadvantage of NFMI is a relatively short near-field wireless transmission range of approximately 1 meter. For this reason, NFMI requires an intermediate relay, typically neck worn, for audio streaming at distances over 1 meter. The signal does not propagate through or around obstacles with the efficiency of lower frequency signals. [4]NFMI systems differ from other wireless systems in that typical wireless systems use an antenna to generate and transmit a propagated electromagnetic wave. Magnetic Induction is based on two principles time varying current in a conductive wire will generate a time varying magnetic field. A time varying magnetic field will induce current into a conductive wire or coil within the magnetic field. By modulating the magnetic field in correlation with specific information such as voice, data or imagery; such information can be transferred between two points.nfmi communications systems operate by inductively coupling a non-propagating, quasi-static, magnetic field between devices. The transmission energy does not radiate 48

2 into free space. The modulated energy is contained in a localized bubble around the communication system [5]. Polling Device Field Near Field Magnetic Induction Data Figure 1. NFMI Communication Sytem While that sounds very complicated, in simplest terms you can think of NFMI as a highly secure, highly scalable Bluetooth replacement. NFMI has several benefits other RF-based wireless communications technologies do not have Reliable Signal Quality, Inherent Security,Spectrum Allocation,Electromagnetic Immunity II. RELATED WORK Listening Device A. Transmitting Information Frequency modulation (FM) and Bluetooth wireless transmission have both been discussed as potential approaches to share information between hearing aids. These are both well known wireless transmission techniques. They also share two important restrictions that make them poor choices for ear-toear transmission: they are both physically large and require significant power. The size and power consumption needs are such that it is simply not possible to fit either of these technologies within the body of hearing aids in a way that would be acceptable to the vast majority of users. An alternative is a technology that is less well known: near field magnetic induction (NFMI) a short-range wireless transmission technique [1]. Because of recent developments, NFMI has enough bandwidth (currently 120 Kbits) to carry both high-quality audio signals and high-content data signals. Its size and power consumption are much lower than is currently possible with FM or Bluetooth. In fact, in one new hearing device, the entire NFMI receiver is implemented in silicon on the hearing aid's integrated circuit and it is small enough to fit inside custom in-the-ear aids. Although this transmission approach uses magnetic, the technology is significantly different from the T-coils that most dispensing professionals know. T-coils respond to a baseband audio magnetic field; there is no carrier frequency and the signal can be directly amplified by the hearing aid. In fact, early T-coils were simply switched in as a replacement for the hearing aid's microphone. As NFMI is applied today, a magnetic field is generated on a carrier frequency and digitally modulated. Receiver circuitry is required to demodulate this signal, recovering the digital information, which could be streaming audio or data packets. Advanced low-power design techniques and power management are used so the wireless functions add only 15 percent to the power consumption of today's digital hearing aids. In its current form, communication is also two-way, meaning that the NFMI unit can act both as a receiver and a transmitter. First, confirm that you have the correct template for your paper size. This template has been tailored for output on the A4 paper size B. Binaural processing technology This binaural processing is applied to the action of other environmentally adaptive signal processing systems. When they are acting independently, the AI enables noise reduction and directional systems are designed to constantly evaluate the environmental conditions and adjust the settings of the adaptive systems based on the immediate conditions experienced by the hearing aid.8 Since conditions such as signal level and S/N can be different on either side of the head, these intelligent systems can make different decisions on either side of the head. Omni with aggressive, noise-only based noise reduction on the right side but split directionality with less aggressive, speech and noise reduction on the left. This is not good for the brain. This will create the impression of something different happening on either ear when the brain's job is to create a fused, unified percept. C. Objectives The primary objective of this paper is a user wearing hearing instruments with the same wireless capabilities would be able to share streaming devices in their home and same streaming devices connected to the television and determine its effect(s) on speech. A secondary objective is to extend with multichannel multipoint voice communication [8] in NFMI Hearing aid. III. A. Existing Systems METHODOLOGY NFMI Technology with one to one communication system: The NFMI technology in the rise platform enables the hearing aids to transmission of audio and data signals at rates of up to 100 Kbps. The hearing aids communicate with each other and with Streamer between mobile phone/media player devices. The inter-aid communication allows for true binaural signal processing and decision making. The communication between the hearing aids and Streamer allows for the transmission of audio signals into the hearing aids is one to one communication and located 50 cm to 60cm. 49

3 B. Proposed Systems The Audio Gateway controller (AGC) is responsible for streaming the source audio to NFMI, at correct sampling frequency (~ KHz). The source of audio will be controlled based on the priority between audio streaming, and phone call (HSP/HFP). It will also apply the configured to mono or stereo channels. The ADC will sample the analog inputs from audio streaming into Digital at KHz sampling frequency (required for NFMI) and send the data to AGC. Similarly, Blue-tooth Module will capture A2DP data and send it over communication channel to the AGC. It will convert this A2DP data at required sampling frequency of KHz. Audio Manager will analyze the data and transmit the either one of the ADC inputs or the A2DP data to NFMI. The decision of which input data to be transmitted over NFMI, will be made by state controller module [7]. Audio music/ phone conversation can be routed to HI s through AGC from Bluetooth enabled mobile phone/streaming devices [8]. simultaneously listening to streamed, amplified audio through their hearing aids. In the case of well vented or open-canal hearing aids, a delay of even 5 milliseconds may degrade sound quality, as the direct, unamplified audio path arrives sooner than the amplified audio. In this system, we used CELT codec and provide high quality audio with very low latency delay for avoid more delay during audio streaming from one system to multiple hearing aid system. i. Working principle of Direct Data Transmission System: 1. AGC device turns on 2. No paired device in the network then the AGC will initiate the paring process using network ID (One hearing aid), more than one generic network ID. Figure 2. Audio Transmission System An important design criterion for audio streaming is excellent sound quality, robust communication, and efficient battery life is provided. This type of hybrid wireless transmission must combat delay in the transmission of audio information. These delays result from the audio data compression and transcoding of standardized wireless protocols, such as Bluetooth, to each manufacturer s proprietary NFMI signal. In the case of audio/video media, delayed audio may result in a lip sync effect, or a lack of synchrony between the video and the streamed audio. The Inter-national Telecommunication Union suggests that audio/video transmission delays should not exceed -40 ms (audio delayed) and +20 milliseconds (audio advanced).listeners tolerance for delay within an audio stream is even smaller when the amplified audio stream and the air- borne, direct audio path are combined, leading to a perceived echo during audio streaming. Small delays in streamed audio may be especially detrimental for patients who enjoy listening to music through open-canal hearing aids. Patients with normal-to-mild, low-frequency thresholds may want to enjoy music through their stereo speakers while Figure 3. Direct Data Transmission System 3. AGC send command to acquire the system information of the hearing aid. Hearing aid, either left or right, in a single hearing aid system 4. If one of them is not found, - display NFMI failure 5. Pairing successful between hearing aid and AGC 6. Start audio streaming from Line- in (connection oriented using PC), A2DP and HFP/HSP [8]. 7. AGC to accept for audio link to hearing aid with NFMI communication. 50

4 8. In a two-hearing aid system, radio channel 1 shall be used for the audio-left channel and radio channel 2 shall be used for the audio-right channel. 9. Stop the audio streaming from AGC or Line-in or A2DP [8] - audio streaming is terminated, the streamer returns to the standby mode. ii. Working principle of Indirect Data Transmission System: 1. AGC device turns on 2. No paired device in the network then the AGC will initiate the paring process using network ID (One hearing aid), more than one generic network ID. 7. Start audio streaming from Line- in (connection oriented using PC), A2DP and HFP/HSP. 8. AGC to accept for audio link to hearing aid with NFMI communication. 9. In a two-hearing aid system, radio channel 1 shall be used for the one pair hearing aid and radio channel 2 shall be used for the another pair hearing aid system. 10. If any one of left /right channel not in range then data shared by left/right channel of within range haring aid system. 11. Stop the audio streaming from AGC or Line-in or A2DP - audio streaming is terminated, the streamer returns to the standby mode. iii. State Transistion Diagram Figure 4. Indirect Data Transmission System Figure 5. State Transition Diagram Data Transmission system 3. AGC send command to acquire the system information of the hearing aid. Hearing aid, either left or right, in a single hearing aid system 4. If one of them is not found, - display NFMI failure 5. AGC is shared by two or more than two pair of hearing aid systems [8]. 6. Pairing successful between hearing aid and AGC. IV. CONCLUSION We have proposed the efficient way of NFMI data transmission from audio source to hearing aid and utilize the bandwidth effectively. The existing implementation only discusses point-to-point communication system. This was extended to support point-to multipoint streaming without any major changes in the architecture in the audio application. We have proposed multiple channel data transmission to overcome the drawback of distance, quality and noise that are often found 51

5 in television. For many users, the ability to access streamed audio from different audio devices, providing additional benefit and assisting them toward successful and use of their hearing aids. Binaural data communication is used to preserve the natural synchronization of the audio data arriving at the two different ears. To ensure that the listener continues to benefit from the effect of multiple data transmissions using advanced codec system without experiencing reduce sound quality. REFERENCES [1] Masihpour, M.; Agbinya, J.I.; Sch. of Comput. & Commun., Univ. of Technol., Sydney, NSW, Australia; Near Field Magnetic Induction: A new technology for embedded medical communication systems; IEEE Transaction on Embedded System, Issue Dec. 2010; [2] Bansal, R.; Connecticut Univ., Storrs, CT, USA - Near-field magnetic communication ; IEEE Transaction on Antennas and Propagation Volume: 46 Issue:2 June [3] FreeLinc Near-Field Magnetic Induction Technology - US Military Whitepaper. [4] Nosowitz, Dan (1 March 2011). "Everything You Need to Know About Near Field Communication". Popular Science Magazine. Popular Science. Retrieved 14 June [5] Groth J, Anthonsen A Fewer wires, less complexity and more connections: The new challenge for wireless hearing instruments. Hearing Review, 17(6), [6] Sjolander M. L., Bergmann, M., & Hansen L. B. 2009;16(11): Improving TV listening for hearing aid users. [7] Beecher F. 2009; 53(10): A vision of the future: 'concept hearing aid' with Bluetooth wireless technology. [8] Kochkin S: MarkeTrak VII: Customer satisfaction with hearing instruments in the digital age. Hear J 2005;58(9): [9] Yanz JL, Preves, DA: Assessing the feasibility of Bluetooth in hearing rehabilitation. Hear J 2007;60(11): [10] Schum D: Redefining the hearing aid as the user s interface with the near and far worlds. Hear J 2007;60(5): [11] Aura Communications: Near field magnetic communication properties. White Paper, S.Senthilmurugan pursuing M.Tech in Computer Science and Engineering. He has published 5 papers in the area of Networking & security.his research includes Embedded System, design and implementation and network security. Mrs.RajapusphaT. Currently working as Associate prof in MVJ College of Engineering, Bangalore. She is guiding 20 students for M.Tech. She has published 11 papers in the area of Networking & Security. Her research interest is security, communication in network, wireless sensor network and Data compression. 52