Since its inception in the late 1990s, Bluetooth technology has revolutionized the delivery of voice and data packets, revolutionizing mobile phones, computers, automotive and consumer electronics.
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In the early days, Bluetooth technology was considered by the authorities to be a "cable replacement" technology with a small application range. Today, Bluetooth technology has become an inseparable feature of many mobile phone designs. The market research firm Forrester also highlighted the fact that the application of Bluetooth technology is shifting from a single mobile phone to other applications, including home entertainment, gaming and automotive applications. In fact, market analyst firm ABI expects that there will be 25 million Bluetooth-equipped cars in the world in 2008. With the development of in-vehicle applications, how will Bluetooth technology be better applied to automobiles, what specific uses, and which technologies will further expand this application? This article focuses on some of the current and future applications of Bluetooth technology, as well as the latest developments in the Bluetooth standard. In these developments, some have enabled wireless technology to fine-tune its performance in accordance with the stringent requirements of the cab environment; and some will open new applications for Bluetooth technology.
In the field of automotive applications, the market for radios, telephony, infotainment and navigation systems with Bluetooth technology is bound to grow rapidly. Not long ago, the Bluetooth products listed in this field were only the phone systems built by car manufacturers on their luxury models. Some of these systems use the driver's mobile phone to communicate via Bluetooth technology, and some replace the early DECT phone with a Bluetooth phone for passengers. Nowadays, more and more car products that offer Bluetooth connectivity are available in the auto parts market, with sellers including professional system installers and major retailers.
Legislation on hands-free equipment in many parts of Europe, the United States, and Asia has led to the creation of various Bluetooth headsets that enable a driver who is driving to make and receive calls through the voice commands of a Bluetooth mobile phone. These headphones are inexpensive and do not need to be installed. They only need to be plugged into the cigarette lighter socket when charging is required. However, they do not form an integral part of an integrated in-vehicle communication system. Later, a car hands-free handset appeared, enabling the driver to communicate via a microphone connected to the control box using a Bluetooth mobile phone. Car hands-free handsets range from a single module that can be plugged into a cigarette lighter socket to a comprehensive model that uses a car stereo system as a loudspeaker, some of which require professional installation. But when making a call, not all plug-in models can silence the radio or stereo in the car, which means the driver still needs manual control. The car CD/MP3 player that supports the Bluetooth hands-free and headphone frame protocol is the first product to leave the single phone mode and can be used for in-car entertainment through the hands-free voice control of Bluetooth mobile phones.
To put Bluetooth technology into your car, you need to solve some problems. Bluetooth technology was originally developed to accommodate harsh applications such as car cabs. This is why some of the world's leading car manufacturers are rapidly adopting Bluetooth technology. For example, CSR's BlueCore chip goes beyond the temperature range of -40°C to +85°C required for cab applications and can operate over the -40°C to +105°C temperature range.
In addition to temperature, other in-vehicle RF devices, such as car stereos, GPS navigation devices, satellite digital audio radio service (SDARS) devices, GSM radio transceivers, and other electrical devices, can cause interference or interference. A car is actually a "can" that can be reflected. The radio waves are reflected in the cab of the car, causing the phase to move. The overlapping phase shifts can eliminate or destroy the desired signal.
These RF signals adversely affect the data traffic of the car's wireless system. As Bluetooth applications expand into infotainment, Internet diagnostics, and other related fields, cars will increasingly be equipped with a variety of Bluetooth devices, further increasing the potential for interference.
Bluetooth technology has a variety of anti-jamming lines of defense. The first line of defense given in the Bluetooth radio specification is frequency hopping, which requires the receiver and transmitter to adjust one of the 79 different channels 1600 times per second in a predetermined pattern. This greatly improves the level of anti-interference, but even with frequency hopping, a large number of RF signals in the car's cab may still adversely affect data traffic and link reliability.
The Bluetooth specification also includes methods to combat any source of RF interference that can be used effectively in the cab of a car. This technology, called CQDDR (Channel Quality Data Drive Rate), monitors noise in the environment, enabling Bluetooth devices to measure how much data is corrupted during transmission, and then dynamically adjust the Bluetooth packet type to best fit The purpose of the environment. In this way, the highest effective data rate can be achieved. If the RF environment of the car's cab is poor, then the chip chosen for the automotive application should incorporate CQDDR to ensure the highest data rate. This is especially true for data applications such as dial-up Internet access, as not all Bluetooth systems incorporate CQDDR.
Currently, Bluetooth links that integrate car entertainment systems with Bluetooth headset hands-free control are only used for audio data with relatively low bandwidth. However, many device manufacturers have recently launched the first Bluetooth stereo headsets on the market, using a new Bluetooth chip specifically designed for stereo sound streaming. Take CSR's BlueCore3 multimedia chip as an example. It integrates a chip battery charger and a digital signal processor (DSP) to improve audio quality and extend battery life. The development of this technology means that future players will allow passengers to listen to music without disturbing the driver.
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