CC3200 is a Cortex-M4 microcontroller with built-in WiFi. WiFi chips. Companies Started Fine Debugging ESP8266 Module Parameters

Figure 9. Graph of the DS18B20 temperature sensor readings in the ThingSpeak service.

Frequently Asked Questions FAQ

• Check if the module is connected correctly;
• Check the correct connection of the Rx, Tx contacts to the UART-USB adapter;
• Check CH_PD pin connection to 3.3V;
• Select experimentally the exchange rate on the serial port.

• Check the correct connection of the DHT11 sensor to the module.

• Check the connection of the module to the WiFi access point;
• Check the connection of the WiFi access point to the Internet;
• Check if the request to the ThingSpeak service is correct.

I propose today to get acquainted with the novelty of amateur radio technology - WiFi module. It is something like the NRF24L01, which has long been familiar to everyone, but is slightly smaller in size and has slightly different functionality. The WiFi module has both its undeniable advantages and some disadvantages, the latter is most likely partly due to the fact that this is a novelty and the developers approached it in a very strange way - information is distributed very tightly (the documentation gives only general ideas about the modules, without revealing their full functionality). Well, let's wait for the indulgence of the company that provided the hardware.

It is worth noting the cost of the module: at the moment it is $ 3-4 (for example, on AliExpress)

Right NRF, left ESP module.

What exactly are these WiFi modules? The WiFi chip itself is located on the board, in addition, in the same case there is an 8051 microcontroller, which can be programmed without a separate microcontroller, but more on that another time, then the EEPROM memory chip is located on the board, which is necessary to save the settings, also on the module board there is all the minimum necessary piping - a quartz resonator, capacitors, a bonus LED indication of the supply voltage and transmission (reception) of information. The module implements only the UART interface, although the WiFi chip allows other interfaces to be used. The WiFi antenna of the required configuration is made on the board as a printed conductor. The biggest part is the 4 x 2 pin connector.

To connect this module to the circuit, you need to connect power to VCC and GND, to TX and RX the corresponding outputs of the UART of the receiving device (remember that RX is connected to TX, and TX to RX) and CH_PD (such as an enable chip, without it everything is on, but nothing works) on plus power.

ESP8266 module parameters:

• supply voltage 3.3 V (moreover, the module itself tolerates 5 V, but the input-output pins will most likely refuse to work)
• current up to 215 mA in transmit mode
• current up to 62 mA during reception
• 802.11b/g/n protocol
• +20.5dBm power in 802.11b mode
• SDIO (two outputs are present on the module board, but they should not be particularly used except for service operations)
• power save and sleep modes to save power
• built-in microcontroller
• AT command control
• operating temperature from -40 to +125 degrees Celsius
• maximum communication distance 100 meters

As mentioned, the module can be controlled using AT commands, but their complete list is not known, the essentials are presented below:

How commands are entered:

• Command execution:<Команда>.
• View status by command:<Команда>?
• Run command with parameters:<Команда>=<Параметр>

When purchasing a module, you can check the firmware version of the module via the AT+GMR command. The firmware version can be updated using a separate software, or with a firmware version from 0.92, this can only be done using the AT + CIUPDATE command. In this case, the module must be connected to a router to access the Internet. Firmware and program for flashing the module up to version 0.92 will be provided at the end of the article. For firmware via software, you need to connect the GPIO0 output to the power plus. This will enable module update mode. Next, select the module firmware file in the program and connect to the WiFi module, the firmware will be updated automatically after the connection. After the update, subsequent firmware updates will only be possible via the Internet.

Now, knowing the organization of the commands of the WiFi module, on its basis it is possible to organize the transfer of information by means of wireless communication which, I believe, is their main purpose. To do this, we will use the AVR Atmega8 microcontroller as a device that is controlled via a wireless module. Device Diagram:

The essence of the scheme will be as follows. The temperature sensor DS18B20 measures the temperature, is processed by the microcontroller and transmitted over the WiFi network with a short time interval. At the same time, the controller monitors the received data via WiFi, when the character "a" is received, the LED1 LED will light up, when the character "b" is received, the LED will go out. The diagram is more demonstrative than useful, although it can be used to remote control temperature, for example, on the street, you only need to write software for a computer or phone. The ESP8266 module requires a 3.3 volt supply, so the entire circuit is powered by a 3.3 volt AMS1117 regulator. The microcontroller is clocked from an external 16 MHz crystal oscillator with 18 pF capacitors. Resistor R1 pulls the reset pin of the microcontroller to the power supply to prevent spontaneous restart of the microcontroller in the presence of any interference. Resistor R2 performs the function of limiting the current through the LED so that neither it nor the output of the MK burns out. This circuit can be replaced, for example, with a relay circuit and the circuit can be used to remote control. Resistor R3 is required for the thermometer to work on the 1-Wire bus. The circuit must be powered from a sufficiently powerful source, since the peak consumption of the WiFi module can reach up to 300 mA. This, probably, is the main drawback of the module - high consumption. Such a battery circuit may not work for a long time. When power is applied to the circuit during its initialization, the LED should blink 5 times, which will indicate the successful opening of the port and previous operations (after turning on the circuit by pressing the reset button, the LED may blink 2 times - this is normal).

You can see the operation of the circuit in more detail in the source code of the microcontroller firmware in the C language, which will be presented below.

The circuit was assembled and debugged on a breadboard, the DS18B20 thermometer is used in the "probe" format with a metal cap:

To "communicate" with such a circuit, you can use either a standard WiFi computer controller or build a transceiver circuit using a USB-UART converter and another ESP8266 module:

Speaking of adapters and terminals, these modules are quite capricious to them, they work well with the converter on the CP2303 and refuse to work adequately with converters built on microcontrollers (homemade), the terminal is best suited for Termite (there is an automatic addition of a carriage return character in the settings, without which the module will also not work adequately with the terminal). But just when connected to the microcontroller, the modules work flawlessly.

So, to exchange information with the microcontroller via WiFi, we will use the second module connected to the computer and the Termite terminal. Before starting work with the circuit, each module must be connected via USB-UART and perform several operations - set the operating mode, create a connection point and connect to the point to which we will subsequently connect to exchange information, AT command to find out the IP address of the WiFi modules (it will be necessary for connecting modules to each other and exchanging information). All these settings will be saved and will be automatically applied each time the module is turned on. In this way, you can save some microcontroller memory on commands for preparing the module for operation.

The modules work in a combined mode, that is, they can be both a client and an access point. If, according to the settings, the module already works in this mode (AT+CWMODE=3), then when you try again to set it to the same mode, the module will return the answer "no change". For the settings to take effect, you need to restart the module or enter the AT+RST command.

After similar settings of the second module, our point called "ATmega" will appear in the list of available points:

In our case, the WiFi scheme will be like this - the module with the microcontroller will connect to the home router (in fact, the microcontroller in this case can access the Internet, if it is registered), then raise the port and act according to the algorithm. On the other side, we will also connect the module to the router and connect to the microcontroller via TCP (as shown in the screenshot, for this you need to set the transmission mode and the number of connections with the AT + CIPMODE and AT + CIPMUX commands, respectively, and enter the command to connect to the server AT + CIPSTART). Everything! If you connect to an access point (WiFi point only, you need to reconnect to the server every time, exactly the same way every time the server needs to be lifted at the other end every time you turn on the power) and restart the module, then there is no need to reconnect yourself, this is also stored in memory and automatically connects when available when you turn on the module. Convenient, however.

Now the temperature data should automatically go to the computer, and the LED can be controlled by commands from the computer. For convenience, you can write software for Windows and monitor the temperature via WiFi.

With the AT + CIPSEND command we send data, when receiving data, the message "+IPD,<айди>,<длинна информации>:" after the colon comes our useful (transmitted) information that needs to be used.

One BUT - it is desirable to power the module not from batteries, but from a stationary power outlet (of course, through a power supply) due to the high consumption of modules.

This is one of the options for transferring information between WiFi modules, you can also connect them directly to each other without a router, or you can connect to the module via a standard WIFi computer and work through it.

The functionality involved is the most obvious of these modules, who knows what else the developers have in store for us!

To program the microcontroller, you need to use the following combination of fuse bits:

In conclusion, I would like to note that this is really a revolution of the Internet of things! With a module price of several green units, we have a full-fledged Wi-Fi module with huge capabilities (which are still limited by the developers of this miracle), the scope is simply not limited - wherever fantasy allows, and given the fact that this module already there is a microcontroller, there is no need to use an external microcontroller, however, which needs to be programmed somehow. So, friends, here's the thing - we give Wi-Fi to every outlet!

The firmware for the microcontroller, the source code in the program, the documentation for the Wi-Fi module chip, the program for updating the module firmware and the module firmware version 0.92 are attached to the article (the archive is divided into 3 parts, because its total size is too large to attach to article), as well as a video demonstrating the operation of the circuit (in the video, the control board connected via WiFi to the control module, the control board periodically transmits information about the temperature, when the thermometer is immersed in water, the video shows that the temperature starts to drop, then if you send the symbol " a" from the control module, the LED on the controlled board will light up, and if the symbol is "b", then it will go out).

That seems to be all. Do not forget to write your comments and suggestions, if there is attention to this topic, we will develop ideas for new ones.

List of radio elements

From Texas Instruments, includes a fully functional WiFi core and a high-performance Cortex-M4 microcontroller with clock frequency 80 MHz and a large set of familiar peripherals. The chip allows you to create complete devices of the Internet of things, using a WiFi network to access the Internet and a variety of wired interfaces to communicate with the outside world.

All resources of the built-in microcontroller are available for the user application - 4-channel 12-bit ADC, 4x16-bit timer, UART, SPI, I2C and SD / MMC interfaces. The multimedia capabilities of the chip include a serial interface for I2S audio transmission and a parallel interface for connecting a video camera. To achieve high data processing speed, the chip has a direct memory access controller (32-channel DMA) and a hardware accelerator to protect transmitted information - an AES-256 encryption node.

Applications for CC3200

• Smart home and intelligent building;
• Security and access control systems;
• Industrial telemetry and wireless sensors;
• Wireless transmission of sound and video;
• Intelligent power supply networks (SmartGrid);
• Access to the Internet and cloud services for any embedded device.

The CC3200 Wi-Fi subsystem includes a separate ARM core that performs all wireless data transfer tasks in a transparent mode for the user and does not require the resources of the Cortex-M4 microcontroller, which is completely at the disposal of the developer. From this point of view, the CC3200 can be viewed as a chip to which an external microcontroller with a Cortex-M4 core was simply added. The CC3200 WiFi radio operates in the 802.11 b/g/n standard and can act both as a base station (“distribute the Internet”) and act as a client, connecting to any regular WiFi router. The air speed is up to 72 Mbps, while the real data transfer rate reaches 12 Mbps in TCP connection mode. The CC3200 differs from other similar solutions by supporting a larger set of secure WiFi network connection modes and provides a reliable secure connection based on TLS/SSL protocols.

The undoubted advantage of the CC3200 is the ecosystem created by Texas Instruments, which includes Wi-Fi and TCP / IP protocol stacks built into the microcircuit, inexpensive debugging tools, sample programs for typical WiFi tasks, and open development of finished WiFi devices for which a complete schematic, list of elements, PCB layout and source code of the executable program.

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INCREASED COMPETITION
The WLAN product sector is currently the largest in the wireless systems market. According to analyst firm IDC, shipments of semiconductor chips for wireless LAN systems will increase from 23.5 million in 2002 to 114.5 million. in 2007, due primarily to the growth of their use in laptops. So, according to the company's analysts, by 2007, 91% of these portable systems will be equipped with 802.11a / b / g chipsets, allowing the user to connect to local networks operating at a transfer rate of 54 Mbps (in accordance with the 802.11g standard) or 11 Mbps (according to 802.11b/a standards) in the frequency band 2.4 (802.11b/g standards) and 5 GHz (802.11a standard). Already in 2003, about 42% of laptops were equipped with Wi-Fi facilities. The use of 802.11a/b/g chipsets in mobile phones won't be that wide. According to IDC, in 2007 the share of handsets with built-in PDA functions based on 802.11a/b/g chipsets will not exceed 5%. At the same time, 802.11b chipsets will cost $5.9, 802.11g will cost $6.8, and dual-band 802.11a/b/g chips will cost $7.4. Fi chips will grow from $599 million to $1.1 billion over the period under review. Not surprisingly, the number of vendors of WLAN chips is also on the rise. All this intensifies competition in the 802.11 chip market, prompting manufacturers to reduce the number of chips in the chipset and expand the functions they perform. A chipset designed to support the IEEE 802.11 standard must contain three main functional blocks:
a transceiver for a frequency of 2.4 or 5.6 GHz;
· a modem that supports orthogonal frequency division multiplexing (OFDM) and CCK modulation;
· a unified media access controller (Media-Access-Controller - MAC), supporting one, two or all three versions of a / b / g of the 802.11 standard, as well as their extensions.
802.11 chipsets on the market today typically include two chips - a MAC / baseband processor * and a radio module. At the same time, the main attention is paid to the creation of chipsets suitable for working with two or three versions of the standard.
The biggest publicity buzz was easily created by Intel in 2003 when it promoted 802.11b mobile technology for Centrino laptops and PDAs**. In 2004, the PRO/Wireless 2200BG mini-PCI Wi-Fi modem was released, supporting versions a and b of the 802.11 standard and providing a transfer rate of 11 and 54 Mbps, respectively, as well as a PRO/Wireless 2915ABG modem that supports all three versions of the standard. The PRO/Wireless 2200BG operates in the 2.4GHz ISM band and supports DSSS (Direct Sequence of Service) technology for connecting to 802.11b networks and OFDM for 802.11g networks. In the 802.11g standard, the modem provides a transmission range indoors of 30 m at a maximum speed of 54 Mbps and 91 m at 1 Mbps, in the 802.11b standard - 30 m at 11 Mbps and 90 m at 1 Mbps. The PRO/Wireless 2915ABG modem operates in the 5GHz UNII frequency band and supports OFDM for 802.11a/g networks and DSSS technology for 802.11b networks. In version a of the standard, the indoor transmission range is 12 m at 54 Mbps and 91 m at 6 Mbps, in version b - 30 m at 11 Mbps and 90 m at 1 Mbps, in version g - 30 m at 54 Mbps and 91 m at 1 Mbps.
Intel's Wireless Compatibility System helps reduce the interference between PRO/Wireless chips and Bluetooth devices. Temperature calibration tools dynamically optimize performance by adjusting power output in response to temperature changes.
However, companies such as Broadcom, Atheros, Philips and IceFyre Semiconductor (Canada) successfully compete with Intel, outperforming it in the release of more advanced 802.11 chipsets costing about $20 in bulk purchases. And the promotion of their products on the market was largely facilitated by the $ 300 million spent by Intel on an advertising campaign for Centrino mobile technology.
In mid-2004, Broadcom announced a single-chip solution for 802.11g WLAN connections. Part of the AirForce One family, this BCM4318 transceiver chip is 72% smaller and cheaper than traditional Wi-Fi modules. Due to this, it will find wide application in laptops, PDAs and consumer electronic devices. The microcircuit is based on BroadRange technology, which uses digital signal processing methods to obtain high sensitivity. It contains a high-performance 2.4 GHz RF unit, an 802.11a/g baseband processor, MAC and other radio components. With a 45% reduction in the number of components used compared to existing solutions, the chip reduces the cost of equipment for networks of home devices and small business devices in which it is used.
The microcircuit supports 54g technology - an implementation of the Broadcom 802.11g standard. This technology provides the industry's best combination of performance, coverage and data protection. The company's 54g-enabled products are compatible with over 100 million 802.11b/g devices installed to date.
The chip includes a power management circuit that extends battery life, and the company's SuperStandby software checks for incoming messages to ensure that the minimum number of elements on the chip are turned on for the shortest possible time. As a result, standby power consumption is 97% less than traditional WLAN solutions.
In addition, the company released a system-on-a-chip - a BCM5352E single-chip router chip that performs routing functions at a speed of 54 Mbps, switching to fast network Ethernet and instruction set processing by the MIPS processor. Both chips support the company's OneDriver software, thus providing high performance and protection.
In the fall of 2004, Broadcom released a 54g standard BCM4320 chip with a built-in USB 2.0 interface. The chip provides the ability to Wi-Fi-connect any device with a USB 2.0 port to local network. By integrating the 802.11a/g MAC/baseband processor, USB 2.0 transceiver, processor core, and memory into one package, the company not only reduced the size and power consumption of the wireless module, but also reduced the cost of materials used by 50%.
One of the most famous designers of MAC chips and processors, as well as software tools for WLAN systems - Texas Instruments. Its TNETW1130 single-chip MAC / baseband processor (Fig. 1) supports 54 Mbps transmission rate in the 2.4 and 5 GHz frequency bands, as well as all three versions of the a / b / g standard 802.11. The chip has been selected by the Wi-Fi Alliance as a design reference used to test the interoperability of 802.11g devices and ensure network interoperability with 802.11b and 802.11g devices. In accordance with the requirements of the 802.11i standard, which provides the highest level of data protection today, the microcircuit contains an accelerator for implementing secure access protocols (WPA) and AES-standard mandatory and optional programs. It also provides a Quality of Service (QoS) support block to perform an extended distributed coordination function and a hybrid coordination function, which can determine the frequency band of emerging applications in real time, such as voice over WLAN, radio transmission, video conferencing, etc. In addition, the functions of the microcircuit include power control during transmission, which allows you to optimize power consumption and extend battery life.
The TNETW1130 chip is mounted in a 257-pin BGA-type package 16x16 mm in size. The package is pin-out compatible with previous generations of MAC/baseband processors.

CONNECT FURTHER, CONSUMP LESS
One of the main areas of work of modern manufacturers of chipsets for 802.11 networks is to increase the range. This parameter for most standard Wi-Fi modems does not exceed 100 m indoors and 300 m in open space in the line of sight. Atheros Communications' AR5004X 4th generation 802.11a/b/g chipset, dual-chip, eXtended Range (XR) technology delivers twice the range, up to 790 m. The chipset provides LAN connectivity any current 802.11 standard anywhere in the world. The chipset includes two microcircuits made using CMOS technology (Fig. 2):
· dual-band "radio station-on-a-chip" (RC) type AR5112, designed for frequency bands 2.3-2.5 and 4.9-5.85 GHz and containing a power amplifier and a low-noise amplifier. For special applications, it is possible to use external amplifiers (power and low noise). The chip eliminates the need for IF filters and most high-pass filters, as well as external VCO and SAW filters. The supply voltage of the microcircuit is 2.5–3.3 V;
· AR5213 multiprotocol MAC/baseband processor supporting RNA. The microcircuit contains blocks for real-time data compression, fast frame and packet transmission, DAC and ADC. Supply voltage 1.8–3.3 V.
The increase in transmission range is achieved by improving the MAC / baseband processor chip, and not the RF chip. The XR technology used in the microcircuit allows tracking, calibrating and interpreting the signals of four OFDM channels. By dropping the transmission rate at long distances, the problem of reducing the peak-to-average power ratio is solved and the coding efficiency is improved.
The data rate of 802.11a is 6-54Mbps, 802.11b is 1-11Mbps, and 802.11g is 1-54Mbps. The chipset also provides the ability to work in Super G and Super AG modes, which use adaptive radio technology and allow automatic detection of free channels in order to ensure maximum throughput. At the same time, the transfer rate reaches 108 Mbps. As a result, a typical user channel bandwidth can exceed 60 Mbps. The receiver sensitivity provided by the chipset is -105 dBm, which is more than -20 dBm better than the value of this parameter given in the standard.
Another important advantage of the new chipset is the reduction in power consumption. Most modern WLAN radios are always on, even when no data is being transmitted or received. The radio based on the new chipset turns off the power when not in use, resulting in a 60% reduction in total power consumption compared to other similar devices (even when operating at 54 Mbps), and the standby current is only 4 mA.
The chipset provides not only wireless network connectivity, but also a theft alarm. In this mode, the kit's chips are not powered off, even if the device they are used in (laptop, PDA, or other host device) is not running. In the event of a theft trigger, the chipset alerts the network to tampering mobile device even if the device is turned off.
Chips of the kit are mounted in a 64-pin leadless plastic case-crystal carrier sized 9x8 mm or in a 196-pin BGA-type case.
At the end of 2004, Atheros announced the creation of the world's first fully functional Wi-Fi module - AR5006X - based on a single-chip AR5413 CMOS chip (Fig. 3), which implements 802.11a/b/g LAN connection. The chip contains a MAC, a baseband processor, and an enhanced dual-band RF unit. With seamless connectivity to any Wi-Fi network, 802.11i support, and support for XR and Super AG modes, the AR5006X will be in high demand among PC, industrial, commercial and consumer electronics end-to-end system manufacturers. The AR5006X not only eliminates one chip from the previous chipset, but also reduces the number of discrete components used by 24. As a result, it was possible to reduce the number of components used in the development of devices by 15% and significantly reduce material costs.
The 802.11a/b/g single-chip AR5413 adopts an advanced wideband receiver that incorporates a channel sequencer with the best transmission conditions, providing longer transmission distance and higher multipath resistance than traditional equalizer-based devices. As with the previous RNC IC, external power and low-noise amplifiers are available for special applications, and all IF filters and most high-pass filters, as well as external VCOs and SAW filters, are excluded. In general, in terms of its parameters, a single-chip microcircuit is comparable to the previous chipset.
The supply voltage is 1.8–3.3 V. The microcircuit is mounted in a BGA-type plastic case 13x13 mm in size.
Mass production of the WLAN device was planned for the fourth quarter of 2004. Its price should not exceed $12 when purchasing a batch of 10,000 pieces.
The opportunities provided by the 802.11 standard, and hence the markets for chips and chipsets for them, are endless. If every pocket computer and cell phone is equipped with support for this standard (or at least part of it), the number of users of such devices will increase from tens of millions to hundreds of millions of people. This will require a large number of chipsets with low power consumption. IceFyre Semiconductor made the first step towards creating such microcircuits, which announced the creation of two chipsets at the end of 2003: one - SureFyre standard 802.11a and the second - TwinFyre to support all three versions of the standard a, b and g.
The SureFyre chipset includes:
· ICE5125 MAC controller chip with low power consumption, supporting 802.11a,b,h,I versions and providing guaranteed quality of data transmission services at a speed of more than 30 Mbps (Fig. 4). The controller architecture can be scaled to provide data rates up to 108 Mbps;
802.11 physical layer chip of the ICE5351 type (according to the developers, at the time the chipset was created, it was the only single-chip physical layer circuit of the 802.11a standard);
· Class F GaAs power amplifier with Chirex summation architecture for 5 GHz type ICE5352, which outperforms traditional class AB amplifiers in the output power range of 40-120 mW.
By improving the design of a traditional OFDM modem, the company's developers were able to fit three computing mechanisms into the ICE5351 physical layer chip. This is the Light Clipper, which limits the ratio of the peak power to the average power of the OFDM signal to an acceptable level; adaptive pre-distortion source; a phase fragmentator that splits an OFDM transmission signal into a set of signals with a constant envelope with a peak-to-average power ratio of 0 dB (Fig. 5).
The TwinFyre chipset includes the same ICE5125 MAC controller and ICE5352 power amplifier chips, as well as a dual-band physical layer chip of the ICE5825 type with an integrated baseband processor that supports CCK modulation, and an 802.11b / g radio module chip of the ICE2501 type, which ensures the operation of the chipset in two ranges.
The output peak power of both chipsets exceeds 1.1W at a transfer rate of 54Mbps. Receiver sensitivity and transmit signal linearity are 10dB and 2dB better than 802.11, respectively. So, the sensitivity of the receiver at a transmission rate of 54 Mbps is -75 dB (against the level set by the standard -65 dB), at the minimum transmission rate (6 Mbps) it is -95 dB. With a delay spread tolerance of 150 ns, as well as antenna spacing and power control for each data packet transmission, indoor range at 54 Mbps and 6% transmission error rate can exceed 40 m. at maximum speed is 2.9 km. In addition, the SureFyre and TwinFyre families of chipsets provide designers with greater flexibility, allowing either a complete system or just the physical layer to interface with an embedded host or proprietary MAC chip. The signal transmission linearity of the TwinFyre chipset when implementing the 802.11b standard is -30 dB, the 802.11g standard is -27 dB. The average RF output power exceeds 20 dBm.
The maximum power consumption of both chipsets is almost half that of competing chipsets, at 720 mW. With these low power costs and aggressive power management, IceFyre's chipsets will be able to connect cell phone or PDA to an 802.11 network. Moreover, these chipsets will facilitate the formation of networks of consumer devices that combine a TV, audio system, set-top box, cable modem, and so on.
IceFyre planned to begin large-scale production of the 802.11a chipset in the first quarter of 2004, and the 802.11a/b/g TwinFyre chipset in the third quarter of the same year. The SureFyre chipset was expected to start at around $20, while the TwinFyre would sell for $5-7 more.

ANSWER TO MIMO TECHNOLOGY
As in any industry, the successful promotion of WLAN systems in the market requires a continuous increase in their bandwidth and improved communication quality. The following three key areas of work to improve such systems can be distinguished:
· improvement of radio communication technology in order to increase the transmission speed;
development of new mechanisms for implementing physical layer modes;
· Improved transmission efficiency to compensate for the performance degradation associated with transmission of headers and switch of the radio to transmit mode.
And with all this, it is necessary to support all three versions of the 802.11 standard. One way to increase the transmission speed of wireless systems is to use multiple antennas at the input and output of the microcircuit for implementing a wireless connection to a local network. This technology, called multiple-input multiple-output (MIMO), or "intelligent" (smart) antenna technologies, uses multipath, which is so undesirable in wireless communication systems, by putting it at the service of these systems (Fig. 6). It allows you to consistently extract information coming through several channels using spatially separated antennas. MIMO technology solves the problem of increasing transmission speed over long distances and full compatibility with already existing standards. And all this without using additional frequency spectrum. According to Wi-Fi semiconductor companies, MIMO will be the key technology to enable the implementation of the 802.11n standard, which supports data rates in excess of 100 Mbps. In the US alone, there are 24 non-overlapping channels on the 5 GHz band and three channels on the 2.4 GHz band. At 100 Mbps data rates for each of these 27 channels, the available bandwidth can reach 3 Gbps.
MIMO technology has been developed since 1995 by scientists at Stanford University, who later formed Airgo Networks (www.airgonetworks.com), which in August 2003 announced the creation of an experimental Wi-Fi chipset of the AGN100 type, made using True MIMO technology based on a unique multi-antenna system and providing a transfer rate of up to 108 Mbps. True, to achieve such a speed, it is necessary to use routers and client boards, which are based on the company's MIMO technology. At the same time, the new chipset is compatible with all existing Wi-Fi standards. Tests have shown that the transmission range of the chipset is two to six times greater than the devices that existed at the time of its release. As a result, the coverage area of ​​each access point (Access Point - AP) has increased by an order of magnitude.
The AGN100 chipset contains two microcircuits - a MAC / baseband processor (AGN100BB) and an RF module (AGN100RF). The chip architecture is scalable, allowing a manufacturer to implement a single antenna system using a single RF chip, or increase throughput by adding additional RF chips. The chipset supports all three versions of 802.11a/b/g and meets the requirements of the accepted working group IEEE 802.11i standard for security and communication security, as well as a standard for the quality of services provided.
The company announced in late 2004 that more than 1 million MIMO chipsets had been purchased in the retail market in one quarter since launch.
The growing popularity of MIMO technology is also evidenced by the fact that at the Consumer Electronics Show (CES), held January 6-9, 2005, a number of OEM companies presented their WLAN systems based on this technology or their description. And many of these systems, including Belkin, Netgear and Linksys, are based on chipsets from Airgo Networks.
The situation is heated up by the demonstration at CES by Atheros Communications of the AR5005VL chipset, which supports MIMO-like operation of systems based on smart antennas. The chipset that supports 802.11g and 802.11a/g versions can work with four antennas and provide 50 Mbps user performance when installed at both ends of the line (when installed at one end of the network line with many different 802.11g standard devices, the performance is 27 Mbps). It uses the technique of phase antenna beamforming and relay cyclic diversity. In addition, the scheme provides advanced signal processing methods that allow you to combine incoming RF signals and thereby increase the intensity and quality of the received signals.
The 802.11a/g chipset is available for $23 for a 10,000-unit purchase, and the 802.11g version for less than $20.
The market for WLAN devices has grown significantly over the past four years, and, obviously, its growth rate will not slow down in the near future. And this opens up great opportunities for manufacturers of the element base of such devices.

WLAN CHIP SUPPLIERS

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