advanced wireless technologies to improve the Hajj services. The 9th of Dil Hajj (12th lunar month of Islamic calendar), the day of Arafat, is the main part of holy ...
Wireless Network Architecture and RF Transceiver Front-end to provide Multilingual Speech Translation and Local Positioning System for Hajj operations M. Anis, Z. Saeed Institute of Microelectronics, University of Ulm, 89081 Ulm, Germany syed.anis @ uni-ulm.de Abstract—This paper presents the wireless network architecture to provide multilingual speech translation and local positioning system during Hajj operations. The pilgrims require low power, low cost and compact ear connected devices to receive the information in their native language. The proposed RF transceiver front-end design consists of multiple numbers of oscillators tuned within spectrum of 5-to-8.5GHz. In transmitting mode, oscillators are periodically turned on and off for short period of time to generate UWB impulses. In receiving mode, oscillators are operated in super-regenerative configuration to detect multi-channel narrowband OOK modulated data bits. Index Terms — Low power, speech translation, local positioning, super-regenerative, oscillator, UWB transmitter.
multi-standard RF transceiver architecture is proposed for the ear connected devices of pilgrims. It consists of UWB impulse transmitter and 5-to-8.5GHz multi-band super-regenerative receiver. The complex UWB receiver and multi-band 5-to8.5GHz transmitter circuitry, which require LNA, mixer, ADCs and frequency synthesizer, are shifted to fixed transceiver located across the holy valleys [2]. The UWB impulses are transmitted to fixed transceiver to locate the current location of pilgrims [3]. The low power multi-band 5-to-8.5GHz super-regenerative receiver with voltage controlled DSSS quenching scheme is required for multiuser environment. II.
I.
WIRELESS NETWORK ARCHITECTURE
INTRODUCTION
Every year Muslims from all over the world gather in the Holy city of Makkah in the Kingdom of Saudi Arabia for pilgrimage called the Hajj. Over the recent past, many efforts have been made to improve transport and infrastructure in order to provide high level of services for visitors from all around the world performing Hajj. This paper presents the advanced wireless technologies to improve the Hajj services. The 9th of Dil Hajj (12th lunar month of Islamic calendar), the day of Arafat, is the main part of holy Hajj in Islam. The pilgrims have to stay in the holy valley of Arafat. The Hajj sermon is delivered from Mosque Nimrah, Arafat which is possible to be listened live in television and radio through the world but unfortunately the pilgrims are unable to listen it in the holy valley of Arafat. This paper presents the multilingual speech translation system to provide live instructions, sermons and announcements to the pilgrims in their native languages. The pilgrims stay in the holy valley of Mina from 8th to 12th of Dil-Hajj. Most of the pilgrims forget the location and direction of their camps. They require guidance in native language during the travelling between Mina-Jamarat and Ka’aba-Mina routes to fulfill the requirements of the holy Hajj. Local positioning system is proposed in this paper for assisting the pilgrims, security officers and crowd management and control unit. The main challenging task in implementation of the proposed wireless communication system is to design and implement portable, small sized, low cost and ultra low power ear connected transceiver for pilgrims. Nowadays, the superregenerative approach has become most attractive for low power wireless systems due to its simple architecture and low power consumption compared to super-heterodyne, low IF and direct conversion transceivers [1]. In this paper, low power
A. Multilingual speech translation system The conceptual diagram of proposed network architecture for multilingual speech translation is shown in figure 1. The transmission flow is unidirectional which reduce the network complexity. The network consists of base transceiver station (BTS), multiple numbers of fixed transceiver (FT) nodes and ear connected transceiver (ECT) nodes available for pilgrims. The real-time instructions, sermons and announcements from administrative authorities are transmitted to BST unit, where the translators provide instant translation in multiple languages. The multilingual translated information from BST node is transmitted to the FT nodes located around the holy valleys of Mina, Arafat and Muzdalfa. The FT nodes further transmit the voice data to ECT nodes to provide instructions, sermons and announcements in native languages of pilgrims. B. Local positioning system Local positioning system can provide guidance to the pilgrims in their native languages, so that the pilgrims can get optimal (nearest and fastest) path from one place to another. The GPS/GIS based technology provides the expensive solution for pilgrims. In this paper, low power and low cost UWB based local position system is proposed. The conceptual diagram of wireless network architecture for local positioning system is shown in figure 2. In local positioning system, the network architecture is complex compared to the multilingual speech translation system. The network can use the same nodes but with different functionality to provide direction and guidance in simple and efficient way. The BTS and FT nodes have distributed digital map information of the holy valleys.
The current position of the pilgrim can be identified by the UWB based positioning and localization techniques between ECT and nearest FT nodes [3].
5-to-8.5GHz band can pass through very narrow spaces due to shorter wavelength and offers the smallest Fresnel diffraction zone compared to 433MHz, 900MHz and 2.4GHz signals. 3) Device efficiency, size and cost Signal wavelength is impacting on device performance, size and cost. In general the products operating on higher frequencies are more compact, having small size of antenna and resonating components. The data transfer rate is higher in 5-to-8.5GHz frequency which is required for tracking, locating or communicating with large number of objects at same time.
Terminals to convey messages in Arabic language FT nodes located across the holy valley
BST station to translate in multiple languages ECT nodes available for all pilgrims
Fig.1. The conceptual diagram of the proposed wireless network to provide multilingual speech translation system The distributed digital map aided local positioning and navigation system can provide the guidance to the pilgrim in their native languages. First the pilgrims or security officers send the request to FT nodes for guidance. The received message at the FT node has the ID number of the pilgrim which contains the information of his camp in holy valleys of Mina and Arafat. All the FT nodes are connected to each other in wireless network and can share the processing load. The FT nodes transmit the voice controlled guidance to the requested ECT nodes to help the pilgrims to reach their camp. C. Wireless Technology The wireless local area networks (WLANs) and Wi-Fi technologies can be used to build network between BTS and all FT nodes. The power consumption, cost and size are not critical design issues for BST and FT nodes. The main challenging task is to define efficient band for communication between FT and ECT nodes which can provide low power, low cost, small size and compact ear connected devices for pilgrims. There are three main criteria to select the technology 1) Traffic in the band The wireless technologies based on 433MHz, 900MHz and 2.4GHz bands have been largely used for short-range communication devices. The usage of these technologies between FT and ECT nodes will suffer from interferences which results in increase in the complexity and the price of device for pilgrims. Therefore it will be more attractive to use a non-crowded band, for instance the 5-to-10GHz band could be the best option to build network between FT and ECT nodes. 2) Communication range and propagation issues The wireless technologies based on 433MHz, 900MHz, 2.4 GHz and 5-to-8.5GHz frequency bands can offer the communication range of 1 to 1.5Km distance at the same transmitted power level. The wireless technology based on
This shows that use of the selection of wireless technologies within 5-to-8.5GHz have multiple advantages compared to other frequencies. This can offer the best compromise between communication range and shorter signal wavelengths to improve the ability to pass through narrow spaces in harsh environments to find the way through dense metallic environments.
BST station
FT nodes located across the holy valley
ECT nodes for all pilgrims
Fig.2. The conceptual diagram of the proposed wireless network to provide local positioning system III. RF TRANSCEIVER FRONT-END The proposed RF front-end of ECT devices consists of impulse UWB (5-to-8.5GHz) transmitter and multi-band FM super-regenerative receivers within frequency range of 5-to8.5GHz. The concept diagram of RF transceiver front end is shown in figure 3. It consists of twelve switchable superregenerative filters to select the preferred language. The audio amplifier provides the interface between the selected superregenerative filter and loudspeaker for ECT devices. In multilingual speech translation system, UWB transmitter is not required during the operation. The ear connected devices require multi-band FM receiver. The control unit enables the filter to select the preferred language. This reduces the complexity of baseband processing unit by eliminating the DSSS demodulation unit for selection between multiple languages. In local positioning system, control unit is required to enable the super-regenerative filters in transmit and receive mode. The UWB impulses are generated to transmit the ID code of pilgrims to the FT nodes. The multi-band superregenerative filters are used to select the native language with DSSS quenching scheme [2]. The DSSS quenching pattern is
based on the ID code of the pilgrims to receive the information for the direction of their camps in holy valleys of Mina and Arafat. SR-BP-Filters
ω0
@
@
Audio Amplifier
ω1 EN
@
ω12
Control Unit
TX/RX
Fig. 3. The concept diagram of RF transceiver front end VDD
Tx/Rx Mode
Tx Data In ID Code
Tx/Rx Mode IA Mux BUF
VG1
Mux
Quench VCO
M1 L
PN Code VREF
C1--8
of the multiplier output to the threshold level. The average of digital demodulated output pattern is compared to the reference voltage to adjust the bias level of oscillator. DC free on-off keying modulation pattern is required to fix the reference voltage at VDD /2. The detailed operation of superregenerative receivers has been previously reported in [5]. The design, implementation and measurement of multi-band superregenerative filters have been presented for UWB radio receivers [6]. In this paper, similar design is presented to build multiple numbers of narrowband super-regenerative filters tuned at different frequencies within 5-to-8.5GHz to select the preferred language. The test structure of twelve reconfigurable super-regenerative filters has been implemented on 0.18µm CMOS technology with an active area of 2.5 mm2, as shown in figure 5. The measurement result of the test structure for narrowband mode with current and voltage controlled quenching scheme has been presented in [7] which can be use to implement low power, low cost and compact ECT nodes for Hajj operations.
Rx Data Demod. Out Unit
Env. Det. OTA
LPF VDD / 2
Fig. 5. The die photograph of twelve superregenerative filters
Fig. 4. The block diagram of super-regenerative architecture IV. The block diagram of super-regenerative architecture is shown in figure 4. The transmitter and receiver are time division multiplexed and share same LC oscillator in transmit and receive modes. The digitally coded ID numbers of the pilgrims are used to turn on and off the oscillator by transistor M1. This generates the UWB impulses of nearly 500ps and transmitted to FT nodes by using buffer between antenna and oscillator [4]. The spectrum of UWB impulses is centered across the frequency of oscillator and covers the bandwidth of more than 500MHz according to the UWB regulations. The complex and power hungry design of UWB receiver is required in FT nodes where power consumption is not the critical issue. The FT nodes can estimate the current location of pilgrim and guide them towards the required direction by transmitting the information in narrowband FM scheme. In receiving mode, quenching of super-regenerative oscillator is made by changing the channel conductance of transistor M1 across the critical level. The amplitude of oscillation envelope is higher than VREF at the end of quench cycle in the presence of the RF signal and lower than VREF in the absence of the RF signal. DC free on-off keying modulated scheme is used to adjust the bias current of the oscillator at critical level by current control loop. The voltage controlled DSSS quenching scheme is required only for local positioning system in multiuser environment. The correlation is performed between the identification code of pilgrim and the output of envelop detector. The output pattern is recovered by the demodulation unit. The simple design of demodulation unit is made by comparing the average voltage
CONCLUSION
This paper presents the advanced wireless communication technique for providing speech translation and local position system for pilgrims and crowd control unit during Hajj operations. Multichannel super-regenerative RF transceiver design is proposed to provide the ultra low power, low cost and compact devices for pilgrims. REFERENCES [1]
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