Abstract: LTE is a new generation of broadband wireless mobile communication technology that is mainstream in the future. Since LTE provides services in the packet domain, it cannot provide circuit domain services like the traditional 3G and 2G networks. Therefore, how to provide voice services in the LTE network has become a problem in the industry. This article mainly introduces the voice service solution of the LTE network, and analyzes the impact of each solution on the traditional network and industry.
LTE (Long Term EvoluTIon) is an international mainstream new generation broadband wireless mobile communication technology. Based on the LTE-oriented system design goal for packet domain optimization, the LTE network architecture no longer distinguishes between circuit domain and packet domain, and adopts a unified packet domain architecture. Under the new LTE system architecture, traditional circuit domain voice solutions are no longer supported, and IMS-controlled VoIP services will be used as voice solutions in future LTE networks.
Since the current performance indicators of VoIP services fail to meet the quality of the existing circuit domain voice services, and the entire network needs to be deployed with IMS, three different voice solutions have been formed on the basis of the existing network: based on the dual standby terminal , CSFB and VoLTE. Both CSFB and VoLTE are LTE voice solutions defined by 3GPP. VoLTE requires full support and optimization of terminals, wireless and core networks. From the current point of view, the implementation complexity is greater. CSFB is a relatively simple voice solution proposed when VoLTE is not implemented in the industry.
1. Voice solution based on dual standby terminals
The dual standby terminal can stand by in the LTE network and the 3G / 2G network at the same time, and can simultaneously receive and send signals from the LTE and 3G / 2G networks. When making a call, the dual standby terminal can automatically select voice communication from 3G / 2G mode. In other words, the dual-standby terminal takes advantage of the fact that it still resides in the 3G / 2G network to answer and make calls from the 3G / 2G network; the LTE network is only used for data services.
The voice solution based on dual standby terminals is a relatively simple solution. The terminal chip can be implemented with two chips (one 3G / 2G chip and one LTE chip) or one multi-mode chip, and the solution is simple. Since there is no interoperation between the LTE and 3G / 2G modes of the dual standby terminal, the terminal does not need to implement different system measurements, and the technology is simple to implement.
Therefore, the essence of the dual standby terminal voice solution is to use the traditional 3G / 2G network, which has nothing to do with LTE. There is no requirement for the network, nor does it need to support any interoperation between the LTE network and the traditional 3G / 2G network.
2. Voice solution based on CSFB
The main idea of ​​the CSFB scheme is to drop back from the LTE network to the circuit domain of 3G / 2G when the user needs to perform voice services, and initiate or answer voice services according to the business process of the circuit domain.
1. Network architecture
To achieve CSFB, it is necessary to establish an SGs interface between the MME and the MSC equipment of the 3G / 2G network. The SGs association plays a bridge role in the CSFB technology, and can connect two different systems to realize the continuity of users' voice services between different systems.
The CSFB technology will affect the existing 3G / 2G network. The MSC of the original network needs to newly add an SGs interface with the MME, and the SGSN adds an S3 interface with the MME.
The wireless subsystem (base station, base station controller) of the original 3G / 2G network needs to increase the neighbor cell configuration of LTE. In order for the terminal to return to the LTE network as soon as possible after the voice service from the CSFB to the 3G / 2G network, the wireless subsystem of the original network needs to support the Fast Return function; The wireless subsystem with network needs to support RIM function, etc.
2. CSFB key technology
The idea of ​​CSFB is to fall back from the LTE network to the circuit domain of 3G / 2G when users need to conduct voice services. The fallback method is to release the LTE wireless link, and the redirection field is carried in the release message, indicating the standard and frequency point at which the terminal re-accesses, called relocation. The relocation method is characterized by simple implementation and a small amount of reconstruction of the original network; the disadvantage is that the delay is relatively large.
In order to reduce the time for the terminal to re-access the 3G / 2G network, 3GPP has proposed a relocation function with system messages, and carries the system messages of the 3G / 2G network in the relocation field. The system message of the 3G / 2G network is transmitted from the BSC / RNC, SGSN, and MME to the LTE eNB through the RIM process. The characteristic of this method is that the delay is small, but the amount of reconstruction of the original network is large, and the original wireless network needs to be modified.
In order to reduce the amount of reconstruction of the original network as much as possible, but at the same time in order to reduce the delay of re-access, the 3GPP specification proposes the DMCR function. The DMCR (Deffered Measurement Control) function allows the UE to fall back to the 3G network and only read part of the system messages during the call, instead of reading all the system messages before the call is established, thereby reducing the call establishment time. However, this function can only be used for 3G networks, and 2G networks do not support the DMCR function.
Another method for supporting terminal fallback from LTE to 3G / 2G network is PS domain handover. This scheme has less delay, but it is more difficult to support, and existing terminals basically do not support this method.
From the perspective of current technical support, industrial implementation, performance, etc., the "relocation method with system messages" is widely accepted by the industry.
2.54mm (0.1") Pitch Female Headers
Overview
The most commonly seen female headers are 2.54mm (0.1") single or double row female/socket headers. These female headers together with its male counterpart are used in connecting Arduino boards and shields together. 2.54mm pitch female sockets/headers are low-profile connectors designed for signal and low power PC board connections when space is at a premium. They have the perfect height for clearing the USB-B connector and great for stacking multiple shields.
Since 2.54mm pitch female header is commonly used in a lot of applications, Scondar offers numerous options for this type of female header. Orientation can either be SMT or THM, single, dual or triple row. Antenk offers 2.54mm pitch female headers in either vertical or right-angle orientation. The pins and blades are also available in various sizes, counts, amperages, and plating.
The 2.54mm can accommodate a maximum current of 3A, with a 30 to 22 AWG wire size, and up to 40-positions. Antenk offers these female headers in high quality and affordable China-quoted price that snuggly fits with the pins of a male header and acts as a receptacle.
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Applications of 2.54mm Pitch Female Headers
Electronics:
LED applications
Arduino boards
Arduino Pro
Arduino Mega
Solar applications
Weighing systems
Appliances:
Air conditioner
Refrigerator
Microwave oven
Washing machine
Water heater
Shower toilet
Washer/Dryer
Stove
Automotive, Heavy Duty Military and Marine
For densely packed equipment requiring weight reduction and downsizing and for tough and harsh conditions.
Vehicle infotainment
Computer peripherals
Battery Connections
Battery connections rely on the ability of the current to pass reliable and solid current. This prevents overheating in the circuit and voltage drop.
Rechargeable battery packs
Battery balancers
Battery eliminator circuits
Medical Diagnostic and Monitoring equipment
Heart monitors
Telecoms
Datacoms
Mount Type: Through-hole vs Surface Mount
At one side of this female header is a series of pins which can either be mounted and soldered directly onto the surface of the PCB (SMT) or placed into drilled holes on the PCB (THM).
Through-Hole (Poke-In)
Best used for high-reliability products that require stronger connections between layers.Aerospace and military products are most likely to require this type of mounting as these products experience extreme accelerations, collisions, or high temperatures.
Useful in test and prototyping applications that sometimes require manual adjustments and replacements.
2.54mm, 1-row vertical female header, 2.54mm, 2-row vertical female header, 2.54mm, 3-row vertical female header, 2.54mm, 1-row right-angle female header and 2.54mm, 2-row right-angle female header, 2.54mm U-
Shaped Female header, 2.54mm U-Shaped Dual Row Female header are examples of Antenk products with through-hole mount type.
Surface-Mount
The most common electronic hardware requirements are SMT.
Essential in PCB design and manufacturing, having improved the quality and performance of PCBs overall.
Cost of processing and handling is reduced.
SMT components can be mounted on both side of the board.
Ability to fit a high number of small components on a PCB has allowed for much denser, higher performing, and smaller PCBs.
2.54mm, 2-row right-angle female header and 2.54mm, 1-row right-angle female header are Antenk`s featured SMT female headers.
Orientation/Pin-Type: Vertical (Straight), Right-Angle and U-Shaped
2.54mm pitch female headers may be further classified into pin orientation as well, such as vertical or straight female header, right-angle female header or U-shaped female header.
Vertical or Straight Female Header Orientation
One side of the series of pins is connected to PCB board in which the pins can be at a right-angle to the PCB surface (usually called "straight" or [vertical") or..
Right-Angle Female Header Orientation
Parallel to the board's surface (referred to as "right-angle" pins).
U-Shaped Female Header Orientation
U-shaped orientation is characterized by the shape of the pins at one side of the header, forming a letter [U". It is often chosen for applications where repeat mating cycles are not required as it can also be used and soldered directly to both PCB's.
Each of these pin-types have different applications that fit with their specific configuration.
Single, Dual or Multiple Number of Rows
For a 2.54mm straight or vertical female header, the standard number of rows that Antenk offers ranges from 1 to 2 rows. However, customization can be available if 3, 4 or n number of rows is needed by the customer. Also, the number of contacts for the single row is about 2-40 pins while for dual row, the number contacts may vary from 2-80 pins.
Pin Material
The pins of the connector attached to the board have been designed with copper alloy. With customer`s demand the pins can be made gold plated.
Custom 2.54mm Pitch Female Headers
Customizable 2.54 mm pitch female headers are also available, making your manufacturing process way faster as the pins are already inserted in the headers, insulator height is made at the right size and the accurate pin length you require is followed.
Parts are made using semi-automated manufacturing processes that ensure both precision and delicacy in handling the headers before packaging on tape and reel.
Tape and Reel Packaging for SMT Components
Antenk's SMT headers are offered with customizable mating pin lengths, in which each series has multiple number of of circuits, summing up to a thousand individual part number combinations per connector series.
The tape and reel carrier strip ensures that the headers are packaged within accurately sized cavities for its height, width and depth, securing the headers from the environment and maintaining consistent position during transportation.
Antenk also offer a range of custom Tape and reel carrier strip packaging cavities.
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ShenZhen Antenk Electronics Co,Ltd , https://www.antenksocket.com