Group Design Project – B202
Product feasibility study
AURAL DELIGHT
Design Requirements
Streaming
One of our functional requirements is that we require audio streaming, and the audio that is streamed must be of a good quality.
My research into this area has bought up A2DP (Advanced audio Distribution Profile). This describes how stereo quality audio can be streamed from a media source to a sink.
For example the source could be an mp3 player and the sink a set of wireless headphones. This is essentially what we are trying to achieve, although slightly different as we have multiple receivers and wish to toggle between them as we please.
A2DP encodes the incoming audio to be transmitted on a blue tooth channel sends the signal wirelessly to a blue tooth receiver that then decodes and plays the audio.
It is designed to transfer a uni directional 2-channel stereo audio stream.
A2DP supports a codec SBC. SBC is an audio encoder and decoder to connect blue tooth audio to other devices such as headphones or loudspeakers.
Requirements
1) Observable / measurable
2) Clear/complete
3) Consistent
Bluetooth adaptor on both ends. The streaming speed of this product is 2.1Mpbs and could be connected wirelessly to at least 5 devices within 1-100m of distance. The product uses subband codec (SBC) for audio and video applications. (SBC enable high quality audio at medium bit rates and obtain at the same time low computational complexity). The product could be used when is charging, as mentioned above it is in small size (portable).
below is some misc:
-wireless protocol for exchanging data over short distance
(PAN)
piconet and ad-hoc computer network
-master and 7 devices in wireless user group
-overcome problems of synchronization
implementation
-use frequency-hopping spread spectrum radio technology
-chops data into 79 frequencies
-data rate 1Mb/s (in Gaussien frequency-shift keying)
uses
-for low power consumption based on low-cost transceiver microchips in both ends
-range: 1/10/100 meters
-radio broadcast communications system = not restricted of the sight
Requirements:
• Provide compatibility between the devices used in the system
• Provide network security
• Be able to connect and transmit audio to other existing devises
• The audio data rate should be sufficiently smaller than usable bit rate on the Bluetooth link. This is to allow retransmission schemes to reduce the effects of packet loss
• Support audio codecs
Example of Configuration
Source (SRC) – A device is the SRC when it acts as a source of a digital audio stream that is delivered to the SNK of the piconet.
Sink (SNK) – A device is the SNK when it acts as a sink of a digital audio stream delivered from the SRC on the same piconet.
Communication and connection:
The Bluetooth Baseband is the part of the Bluetooth system that specifies or implements the medium access and physical layer procedures between Bluetooth devices.
Two or more devices share the same physical channel. One Bluetooth device acts as the master (SRC), whereas the other devices act as slaves (SNK). The master device can communicate with up to seven devices in a Wireless User Group. This network group of up to eight devices is called a piconet.
Bluetooth Clock:
Every Bluetooth device has a native clock that shall be derived from a free running system clock. For synchronization with other devices, offsets are used that, when added to the native clock, provide temporary Bluetooth clocks that are mutually synchronized.
Air interface:
The Bluetooth protocol operates in the license-free ISM band at 2.4-2.4835 GHz dividing the band into 79 channels (each 1 MHz wide) and changes channels up to 1600 times per second.
Audio codecs:
Define the capability field and its parameters necessary for signaling procedures in the streaming set up.
Support of Codecs
The table shows supported Mandatory and Optional codecs.
Mandatory Codec
The Advanced Audio Distribution Profile (A2DP) mandates low complexity subband codec (SBC) to ensure the interoperability. The device shall implement a SBC encoder when the device is the SRC, and a SBC decoder when the device is the SNK.
Optional codecs
The device may also support Optional codecs to maximize its usability. When both SRC and SNK support the same Optional codec, this codec may be used instead of Mandatory codec.
Security:
Bluetooth is extremely secure in that it employs several layers of data encryption and user authentication measures. Bluetooth devices use a combination of the Personal Identification Number (PIN) and a Bluetooth address to identify other Bluetooth devices. Data encryption (i.e., 128-bit) can be used to further enhance the degree of Bluetooth security. The transmission scheme (FHSS) provides another level of security in itself. Instead of transmitting over one frequency within the 2.4 GHz band, Bluetooth radios use a fast frequency-hopping spread spectrum (FHSS) technique, allowing only synchronized receivers to access the transmitted data.
Range of Bluetooth transmitter/receivers:
The range for bluetooth communication is 0-30 feet (10 meters) with a power consumption of 0dBm (1mW).This distance can be increased to 100 meters by amplifying the power to 20dBm.
Bluetooth 1.1 & 1.2 transmission speed up to 721 kbit/s
Bluetooth 2.0 transmission speed up to 2.1 Mbit/s
Case Scenarios
Student
Many students like Mike use the Phone as an alarm. So Mike, who has just made an investment in ‘Aural Delight’ has made the right choice, after barely minutes of setting up he has been able to make his music work for him. Now when he gets up in the morning it is a dead certain that he won’t sleep through that alarm again as he has the transmitter on his phone connected to the receiver on his Hi-fi system. As such he has a considerably louder and better sounding music to get him up in the morning. Once Mike has aroused himself from his pit of despair of being ripped away from x-rated night tine recreation thrown on some clothes theirs a feeble groan of pain and excitement with the anticipation of a new day forming. Of course this groan is in fact a warning sign that Mike is hungry. As such he stumbles down stairs and into the Kitchen where he proceeds to make Breakfast and a quick cup of coffee all the while he has his Favorite music radiating from room to room, until he settles down in the living room to devour that which is on his plate as he music continues to surround him from the TV for his ‘Aural Delight’ has blistering speeds and fantastic functionality all the while all mike needs to do is walk around with his MP3 or Mobile phone connected to the ‘Product still to be named’ for blissful aural delight.
Business man
I would like to tell you a story about a good friend of mine whom we will call 'Norman Brunswick' for privacy reasons. This man is a good man, with a good job and a loving family. In his job is is always on the move moving from building to building as 'company X' most valuable troubleshooter. In his job, and life he will always have an amazing collection of music out and about for in his career he works as a marketing Executive and as such works on many TV and Radio adverts. Due to this his always has a collection of music on his person so that he can pick out 'PHAT TUNEAGE' that would be perfect for any such device. The reasons why he likes to work with out wires is that he is a energetic sales man and likes to move about and talk through his ideas with several different pieces of Music. And as such finds it utterly Contmetabul the ideas of having to remain in a fixed place to change from track to track. After a hectic day of travel and Tunes he likes to relax at his house with the ability to keep up to date with the latest music. One of the advantages that Norman is offered is the convenience of having his choice of Music for relaxing to until its time to cook the Sunday roast so he can just walk through and continue with his Aural Delight.
Female Case Study
Vera is a Professional Athlete, An Endurance runner and Climber. And as such benefits from the use of 'No Wires', also due to the use of her Music player she can organize the best playlists to help her keep in time and Motivated. Of course the best reason for her to have the ability to move the transmission of music from receiver to receiver and terminal to terminal after she has returned home so that she can just sit down and relax after a long day a training. When competition comes around Vera has always preformed at her best when in a world of her own, and due to this the ability to go about competing without the risk of accidental knocking of wires and pulling out her earphones whilst on the move.
Concept Diagram
Central Idea:
The objective is to have an audio streaming device over Bluetooth which can in vicinity of the receivers easily switch from one receiver to another.
Examples of use:
Imagine having a stereo system on your workplace, another couple of them at your home and your car system stereo.
With any music device with output, connected to the transmitter and each of the receivers previously installed on the audio systems you want to stream to.
You wake up at your house and the music your streaming goes to your television, you get into the car to go to work and the same track continues to play with a push of a button, and when you get to work with another push of a button it will continue in your office audio system with the track.
Device specifications:
Both will be stylish and modern design with for example gloss black finish. Blue led lights and detailing or silver chrome.
Transmitter:
- 3.5mm connecting jack
- Long life rechargeable battery
- Led to notify the receiver you are transmitting to.
- Button (single press to switch between receivers/ long press to pair with receivers)
- Slide out power connector for charging of receiver stations
Receiver:
Comparisons to Existing Products
These following products are already in existence and in this part of the feasibility study we will be comparing the functionalities of these products to our own.
• iBluon BT-TD02 Bluetooth Audio Transmitter For iPod
• Zoom iHiFi Wireless Bluetooth Music Transmitter/Receiver Bundle
• Sony TMR-BT8iP Bluetooth Wireless Transmitter for iPod
• Satechi SRS-200BD Bluetooth Audio Transmitter Adapter for iPod
The Similarities
All of these products, including are own design have a similar function. Therefore there are some basic similarities that we cannot escape from.
All the products use
• Bluetooth version 2.0
• Class 2 Bluetooth power specification (30 feet transmission if the line of sight is unobstructed.)
• A2DP profile ( this profile supports audio streaming to a Bluetooth receiver)
Our product will be similar to the SRS-200BD in the way that we wish to make pairing devices easy. This could be achieved by using an auto connection algorithm. Although if cost is an issue with Aural Delight an auto connection algorithm may be an expensive function to implement. Conversely, buttons to pair devices would not require any extra processing power to implement and may prove to be a more viable choice.
The Con’s
Our product does not implement all the functionalities available in the products we are comparing it too. The main difference in our product in comparison to these four is AVRCP. This is a Bluetooth profile which acts as a control system for other Bluetooth devices. AVRCP or (Audio/Video Remote Control Profile) allows the Bluetooth transmitter to also have separate remote control functionality, for devices such as TV’s Hi-fi systems. This profile can be used in conjunction with A2DP as an audio streaming profile. This means that out product has less functionality than the immediately related products.
The Pro’s
Although our product does not include all the functionalities of the products that are similar and already in existence, we believe that this will be an advantage. Because of the reduction in functionality we will be able to reduce the overall cost of the product .
Another advantage of our product against existing products is that it will support ADTVP. This profile is standard for establishing and breaking connections between other Bluetooth devices. ADTVP also supports multiple receivers paired to a single transmitter. As our device is portable this is an extremely useful functionality, effectively you could stroll through your house, area or workspace changing the receiver you are pairing too.
Another advantage of our product is that is is more universal in what it can be connected too. The other products we have been reviewing are all confined to ipod connections thus this limits their use to people with an Ipod. Our product has a 3.5mm jack connection which could be used to plug into various devices for example you could stream from a non-ipod mp3 player or even from your phone. One of the existing products "Zoom iHiFi Wireless Bluetooth Music Transmitter/Receiver Bundle" does connect to a 3.5mm jack but does not support ADTVP and therefore cannot pair to multiple receivers.
In conclusion, although our product is lacking in some functions provided by similar products. This decrease in functionality could provide an opportunity to reduce the overall cost of our product. Also, the universal connectors will make it more accessible to a wider variety of consumers combined with this reduction in price.
Key cost Drivers
As the result of the broken-up value chain of the world, design becomes an independent commodity. Goods often are designed in one company and produced in another company. Although product is shaped in manufacturing companies of supply chain, design quality is the key sticking-point for product quality. Therefore, finished goods quality lies on the quality of Design-Manufacturing Chain.
With 80% of the total cost of a product committed by the end of the design process, the greatest opportunity to effect changes in product cost, quality, and performance occurs early within the design process. It is during the design concept and development phases when companies can benefit most from supplier expertise on materials, parts, products, and processes.
Production Management
The part of the design which will affect the cost the most is the production management. In today’s business-to-business environment, a collaborative supply chain is a must. At the heart of supply chain management is the question: What is the best way to coordinate the acquisition, production, storage, and movement of goods and materials across the supply chain to meet specific demand elements, such as customer orders, sales forecasts, or inventory level targets? The supply chain consists of physical locations through which raw materials and finished products flow and the resources that transport the goods between locations – from original suppliers to production plants, warehouses, and distribution centers, all the way to the final demand source, the customer. So the plans of how to coordinate all material supply, production, and distribution have to be done and optimized. Plans must bring about the highest possible levels of customer service at the lowest possible cost.
Hardware
Our product requires a few hardware components, and they will also affect the cost of the product. The transmitter employs a heterodyne approach to create the 2.4 GHz output signal, reusing and modifying several components from the receiver design. The module is very simple to operate and offers low current consumption (typ. 4 mA). Data can be supplied directly from a microprocessor or encoding device, thus keeping the component count down and ensuring a low hardware cost. The module exhibits extremely stable electronic characteristics due to the use of ‘Thick-Film’ hybrid technology, which uses no adjustable components and ensures very reliable operation. And the receiver has very high frequency stability over a wide operating temperature even when subjected to mechanical vibrations or manual handling. A unique laser trimming process which has been patented gives a very accurate on board inductor, removing the need for any adjustable components. The receiver requires connections to power and antenna only.
Quality of transmission
Another cost driver which has to be considered is the quality of transmission. The Frequency-hopping spread spectrum (FHSS) will be implemented in our product for that purpose. FHSS is a transmission technology where the data signal is modulated with a narrowband carrier signal that "hops" in a random but predictable sequence from frequency to frequency as a function of time over a wide band of frequencies.
Spread-spectrum signals are highly resistant to narrowband interference. The process of re-collecting a spread signal spreads out the interfering signal, causing it to recede into the background. And the Spread-spectrum transmissions can share a frequency band with many types of conventional transmissions with minimal interference. The spread-spectrum signals add minimal noise to the narrow-frequency communications, and vice versa. As a result, bandwidth can be utilized more efficiently.
Interface
Due to the Bluetooth spectrum Band being unlicensed in the ISM band (in which the USA, Europe [excluding Spain and France] uses 2.4000 – 2.4835 with 79 bands) there is little chance of the spectrum being used up due to most Bluetooth devices running at 10 meters standard. It has also been stated from an ‘Intercai mondiale white paper’ that the production of a sophisticated Bluetooth interface will be $10.
Strength of connection
Another cost Driver will be the distance of the connections between the Transmitter and Receiver. In our case we have said up to 10 meters of distance and so a class 2 connection would be most suitable for this application. The reason why we have chosen class 2 is twofold, First class 1 is for a connection range of up to 100m and as such requires a large power of 100w to operate. The second reason being that class 2 has a range of around 10m but only takes 2.5w to power. From reading this you can understand that class 2 Bluetooth will be cheaper in production for the actual Transmitter.
Level of security
Security conditions, is yet another condition we will need to ask in order to consider the Price point of the finished production in comparison to the cost of production. In security it will all depend on the level of security needed. Obviously we won’t need anything to complex due to the distance of transmission and due to lower complexity the speed of the transmission will be better. I believe that level 2 security will then be our choice of security. In level 2 security trusted devices will be accepted. This will be set up via the packaged software and as such will be relatively cheap and very cost effective.
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