What is the Difference Between UMTS and EDGE?

EDGE is the abbreviation of English Enhanced Data Rate for GSM Evolution, that is, enhanced data rate GSM evolution technology. EDGE is a transition technology from GSM to 3G. It mainly uses a new modulation method in the GSM system, namely the most advanced multi-slot operation and 8PSK modulation technology. Since 8PSK can expand the symbol-carrying information space of the GMSK modulation technology used in the existing GSM network from 1 to 3, the information contained in each symbol is 3 times the original. Also named the Gladiator Edge.

The reason why EDGE is called

GSM and TDMA / 136 are now the world's second-generation cellular mobile communications standards. Currently, more than 100 million people in more than 100 countries use GSM, and about 95 million users in nearly 100 countries use the TDMA / 136 system family (including ELA-553 and IS-54) services. As between existing

According to the latest research by Visitant Strategies, global mobile operators will use EDGE (Enhanced Data Rate Transmission Service) technology as a permanent data service repair or as a transitional solution that can enhance data and voice services in the coming years. Although many operators canceled EDGE not long ago, this technology is now regarded by operators as a practical option for providing high-speed data services and capacity upgrades to current GSM or TDMS.

By 2009, hundreds of thousands of EDGE-enabled base stations will be established worldwide. Therefore, EDGE technology has delayed the sales of next-generation equipment in most parts of the world. In addition, the study also found that the chip market for mobile phone EDGE accessories will reach $ 2 billion in 2009, and total mobile phone sales such as GSM / GPRS / EDGE will be $ 31 billion.

Visant's in-depth analyst Andy Fuertes said: "It is expected that the functionality of EDGE technology will soon be absorbed into mobile phones, just as GPRS functionality has become popular in mobile phones this year. Most UMTS / GSM dual-mode phones will be in the next 5 years Both will have EDGE capabilities, making EDGE capabilities one of the important criteria for customers to choose their phones. "

Research indicates that in 2009, all EDGE users will exceed 130 million. Many EDGE users will also adopt other technologies such as UMTS or OFDM.

Larry Swasey, another author of the study, said: "From population density, average capital gains, wireless penetration, and overall

1: Your area covers an EDGE network.

(Some medium and large cities generally have EDGE. If your city has EDGE, it will automatically use EDGE, if not, it will automatically use GPRS.)

2: Your phone supports EDGE.

(You can refer to the instructions of your mobile phone. In addition, some mobile phones actually have EDGE function, but they are blocked and not turned on)

How to know if your phone is using the EDGE network.

Just look at the network icon of your phone

EDGE is a small "E" and GPRS is a small "G"

EDGE is an important technology that can further improve the transmission rate of mobile data services and the transition from GSM to 3G. It has the following characteristics in terms of access services and network construction

Voice communication is the main service of the second generation mobile system. In recent years, mobile communication devices have greatly enhanced their ability to support data communication. Some standard mobile communication devices can currently provide data services at rates up to 9.6 kbps. However, such a low data communication rate obviously cannot meet the needs of mobile device multimedia data communication. Therefore, manufacturers are developing new and faster mobile data communication technologies, the most typical of which is GPRS (

EDGE is a data-enhanced mobile communication technology based on the GSM / GPRS network, and is often referred to as the 2.75-generation technology. In 2003, EDGE, which was once neglected, became a bright spot in the mobile communications market. CingularWireless and AT & TWireless in the United States, TelefonicaMoviles in Chile, CSL in Hong Kong SAR, and AIS in Thailand opened EDGE-based services. At the same time, some European mobile operators have also begun to show interest in EDGE. Both TIM and TeliaSonera have clearly stated that they will use EDGE technology.

From a technical point of view, EDGE provides a new wireless modulation mode that provides three times the speed of ordinary GSM air transmission. On the other hand, EDGE has inherited the GSM standard standard. The carrier frequency can dynamically switch between GSM and EDGE based on the time slot (based on the type of mobile phone), supporting traditional GSM mobile phones, thereby protecting the investment of the existing network. The EDGE network can be flexibly and gradually expanded, which provides favorable support for operators to maximize value.

EDGE (Enhanced Data GSM Environment) is a faster

The improvement of wireless data communication speed puts forward new requirements for the existing GSM network structure. However, the impact of the EDGE system on the existing GSM core network is very limited, and because GPRS nodes, SGSN, and Gateway GPRS Support Node (GGSN) are more or less independent of user data communication rates, EDGE will not require the deployment of new hardware .

An obvious communication bottleneck is the A-bis interface, which currently only supports a rate of 16kbps per channel slot.

For EDGE, the rate of each channel will exceed 64 kbps, which requires multiple A-bis time slots to be allocated for each communication channel. However, the 16-kbps limit of the A-bis interface can be broken through the introduction of two GPRS coding schemes (CS3 and CS4), which can provide a rate of 22.8 kbps per communication channel.

For GPRS-based packet data services, other nodes and interfaces have been able to handle higher bit rates per time slot. For circuit-switched services, the A-bis interface can handle a rate of 64 kbps per user, so modifications in the MSC will only affect the software part, and will not involve the original hardware equipment.

(1) Wireless network planning

An important condition for the success of EDGE is that it should allow network operators to gradually introduce EDGE. EDGE-capable transceivers should first be deployed where EDGE coverage is most needed to complement existing standard GSM transceivers, so circuit-switched, GPRS, and EDGE user services will coexist in the same frequency band. In order to minimize operator investment and costs, implementations related to EDGE should not require extensive modifications to existing wireless network planning, including cell planning, frequency planning, power level and other cell parameter settings.

(2) Coverage planning

An important feature of non-transparent radio link protocols (such as those that include automatic repeat request for APR) is that poor radio link quality results in lower bit rates. Unlike voice communications, a low carrier-to-noise ratio does not cause a loss of data sessions, but only temporarily reduces the user's communication speed. Carrier interference between different users in a GSM cell. An EDGE cell will include users with different communication rates at the same time. The communication rate is high near the cell center, and the communication rate is limited to the cell border. Within the range of standard GPRS.

According to the test results provided to the International Organization for Standardization, an EDGE system with 95% of voice communication services will have 30% of users obtain a communication rate per time slot of more than 45Kbps, and the average rate of all users is 34Kbps. Assuming the APD is 2dB, the average communication rate will be reduced to 30Kbps.

In terms of coverage, if the network operator can accept only standard GPRS data communication rates at the distant borders, then existing GSM sites have already provided sufficient coverage for EDGE. For transparent data services that generally require a continuous bit rate, link adaptation technology must be used to allocate the number of time slots when the bit rate and error bit rate (BER) requirements are met.

(3) Frequency planning

In most mature GSM networks, the average frequency of frequency reuse is between 9-12, and future mobile communication systems will develop towards lower frequency reuse. In fact, with the introduction of frequency hopping technology, multiple reuse methods (MRP) and discontinuous transmission (DTX) are feasible to reduce the frequency reuse frequency to 3, which means that every 3 base stations will be frequency Case of reuse.

EDGE supports this development trend of frequency reuse. In fact, due to the use of link adaptation technology, EDGE can be introduced into any frequency plan, including EDGE can be introduced into the existing GSM frequency plan, laying a good foundation for future higher-speed data communications.

(1) The bandwidth has been significantly improved. The single-point access rate peaks at 2 Mbit / s, and the single-slot channel rate can reach 48 kbit / s, so that the transmission rate of mobile data services can reach 384 kbit / s at the peak. This is mobile The realization of multimedia services provides the foundation.

(2) A more accurate network layer provides location services.

(1) EDGE is a modulation and coding technology that changes the rate of the air interface.

(2) The air interface characteristics such as EDGE's air channel allocation mode and TDMA frame structure are the same as GSM.

(3) EDGE does not change the structure of the GSM or GPRS network, nor does it introduce new network units, but only upgrades the BTS.

(4) The core network uses a three-layer model: the business application layer, the communication control layer, and the communication connection layer. The interfaces between the layers should be standardized. Adopting a hierarchical structure can make call control and communication connections relatively independent, which can give full play to the advantages of a packet-switched network, and make the traffic and bandwidth allocation closer, especially suitable for VoIP services.

(5) Media Gateway (MGW) is introduced. MGW has STP function, which can realize the establishment of signaling network in IP network (requires VPN support). In addition, MGW is not only the interface between GSM's circuit-switched services and the PSTN, but also the interface between the Radio Access Network (RAN) and the 3G core network.

(6) The speed of EDGE is high. The existing GSM network mainly uses Gaussian minimum frequency shift keying (GMSK) modulation technology, while EDGE uses octal phase shift keying (8PSK) modulation, which can reach 473.6kbit in a mobile environment. / s, can even reach 2Mbit / s in a static environment, which can basically meet the needs of various wireless applications.

(7) EDGE supports both packet-switched and circuit-switched data transmission methods. The packet data services it supports can achieve rates of up to 11.2kbit / s-69.2kbit / s per time slot. EDGE can support circuit switched services at a rate of 28.8kbit / s. It supports both symmetric and asymmetric data transmission, which is very important for mobile devices to access the Internet. For example, in the EDGE system, users can use higher rates in the downlink than in the uplink.

The main role of the EDGE wireless interface is to enable current cellular communication systems to achieve higher data communication rates. The existing GSM network mainly adopts GMSK modulation technology. In order to increase the overall rate of the wireless interface, a modulation scheme capable of providing a high data rate is introduced in EDGE, that is, octal phase shift keying (8PSK) modulation. Because 8PSK expands the signal space of GMSK from 2 to 8, each symbol can include 4 times the information. The symbol rate of 8PSK is maintained at 271kbps, and a total rate of 69.2kbps can be obtained per time slot, and the GSM spectrum mask can still be completed.

The basic guiding idea of the EDGE specification is to use as many existing GSM data service types as possible to greatly increase its data communication rate. It defines several channel coding schemes to ensure the robustness of various channel environments, and uses link adaptation technology to achieve dynamic conversion between coding and modulation schemes. By using the GPRS structure again, the packet data service can achieve a wireless communication rate of up to 11.2-69.2kbps per time slot. EDGE supports circuit-switched services by using a high-speed wireless interface rate of 28.8 kbps per time slot.

In the EDGE solution, the multi-slot communication that supports all services is 8 times faster than the single-slot communication, and the peak wireless communication rate for packet data services can be as high as 554kbps.

(1) Impact on wireless interface equipment

EDGE's modification of the original wireless interface of the GSM network will directly affect the design of base stations and mobile terminals. People must use new terminals and base station transceivers to send and receive information using EDGE modulation.

(2) Influence on linear modulation

The new modulation scheme places new requirements on the linearity of the power amplifier. Unlike GMSK, 8PSK does not have a fixed package. In fact, the biggest challenge facing EDGE is to create a cost-effective transmitter, and at the same time complete the GSM spectrum shielding.

In order to maximize the use of existing GSM networks, EDGE transceivers must be installed in a base station bay designed for standard transceivers, and EDGE transceivers must be acceptable in terms of transmit spectrum and thermal dispersion. Generally, a high-performance EDGE transceiver may need to reduce its average transmit power when transmitting 8PSK. Compared with GMSK, the average power reduction (SPD) is between 2-5dB.

How to design a low-power transceiver, namely a pico base station, an indoor or picobase, and a mobile terminal will bring further challenges. For example, in an EDGE system, a transmitter structure optimized for nonlinear modulation can no longer be used.

There are two modulation methods that can be used where a mobile terminal is connected. The first is to use GMSK transmission for the uplink and 8PSK for the downlink. In this way, the uplink rate will be limited to the range of GPRS, and the high rate of EDGE will be provided for the downlink. Because most services have higher requirements on the downlink rate than the uplink, this solution can meet the service needs of mobile terminals in a most economical way. The second method is to use the 8PSK transmission method in both the uplink and the downlink.

The existing GSM standard defines a variety of mobile terminals, such as from single-slot devices with low complexity to 8-slot devices with high ratio characteristics.

(3) Impact on total rate

The higher the overall interface rate, the more complicated the technology. The high rate of the EDGE interface cannot be handled by the optimal equalizer structure, but only the sub-ideal equalizer design can be considered. Based on the results of the simulation tests, the best equalizer design for 8PSK will only be slightly more complicated than the standard GSM equalizer.

The enhanced bit rate (compared to standard GPRS) also reduces robustness in terms of time distribution and mobile terminal speed. However, in most cases, EDGE services will be used by relatively stationary users, which means that high-speed movement and excessive time distribution of mobile terminals are not possible. In addition, when the movement speed and time distribution exceed the capabilities of EDGE, GMSK modulation is still needed.

With the introduction of EDGE, a cell will include two types of transceivers: standard GSM transceivers and EDGE transceivers. Each physical channel (time slot) in a cell typically has at least four channel types:

(1), GSM voice and GSM circuit switched data (CSD);

(2) GPRS packet data;

(3), circuit switched data, enhanced circuit switched data (ECSD) and GSM voice;

(4) EDGE packet data (EGPRS), which allows services to be provided for both GPRS and EDGE users.

Although standard GSM transceivers only support the above channel types 1 and 2, EDGE transceivers support all 4 types mentioned above. The physical channel in the EDGE system will be dynamically defined according to the terminal capabilities and cell requirements. For example, if several voice users are active, the number of Class 1 channels will increase, while reducing both GPRS and EDGE channels. Obviously, in the EDGE system, it is necessary to be able to realize the automatic management of the above four channels, otherwise the efficiency of the EDGE system will be greatly weakened.

The so-called link adaptive LA is the ability to automatically select modulation and coding schemes to meet the needs of wireless link quality. Link adaptive dynamic selection algorithms supported by the EDGE standard include measurement and reporting of downlink quality, and selection of new modulation and coding methods for the uplink. Link adaptation means full automation of modulation and coding. The possibility of improving ARQ performance through incremental redundant IR (hybrid II / IIIARQ) is also being studied. Such a scheme can reduce the need to use link adaptation technology when selecting modulation.

Common points of link adaptive LA and incremental redundant IR:

1. Both LA and IR are actively controlled by the network, and the mobile phone responds passively.

2. LA and IR may be switched in the same connection. For example, when the memory of the mobile phone is insufficient, downlink data transmission may be switched from IR to LA.

3. The retransmission data block can adopt different encoding methods, can adopt a lower encoding method, can also adopt a higher encoding method, and can only adopt the encoding method of the same family.

Current GSM systems use dynamic power control to increase equality in the system and extend the life of the mobile terminal battery. Similar strategies will be used for GPRS. Although their actual signaling process is different, EDGE's support for power control is considered by experts to be similar to GSM / GPRS. Therefore, the network operator only needs to modify the parameter settings of the existing GSM / GPRS network when deploying EDGE.

It needs to be added that because EDGE users can benefit from a much higher carrier-to-interference ratio than standard GSM users, the power control parameter settings of EDGE will be different from GSM / GPRS.

EDGE bearer services include packet services (non-real-time services) and circuit-switched services (real-time services). The bearers of these services include the following two:

1. Packet Switched Service Bearer

The GPRS network can provide an IP connection from a mobile station to a fixed IP network. For each IP connection bearer, a QoS parameter space is defined, such as priority, reliability, delay, maximum and average bit rate, and so on. Through different combinations of these parameters, different bearers are defined to meet the needs of different applications.

For EDGE, a new QoS parameter space needs to be defined. For example, for a mobile station with a mobile speed of 250 km / h, the maximum code rate is 144 kbit / s, and for a mobile station with a mobile speed of 100 km / h, the maximum code rate is 384 kbit / s. In addition, the average bit rate and delay level of EDGE are also different from GPRS.

Because different applications and different users have different requirements, EDGE must be able to support more QoS.

2. Circuit switched service bearer

Existing GSM systems can support transparent and non-transparent services. It defines 8 types of transparent service bearers and provides a bit rate ranging from 9.6 kbit / s to 64 kbit / s.

Non-transparent service bearers use wireless link protocols to ensure error-free data transmission. In this case, there are 8 types of bearers, and the provided bit rates are 4.8kbit / s to 57.6kbit / s. The actual user data bit rate varies with channel quality.

Tcs-1 is implemented by occupying 2 time slots. For the same service, TCH / F14.4 for the standard GSM system needs to occupy 4 time slots.

It can be seen that the circuit switching mode of EDGE can use less time slot occupation to achieve higher speed data services, which can reduce the complexity of mobile terminal implementation. At the same time, since the number of time slots occupied by each user is less than that of the standard GSM system, the capacity of the system can be increased.

OpenBSC is an open source

The new term EDGE gradually attracted people's attention in the middle of 2007. First of all, mobile tested the EDGE network in a few cities in the south. At that time, users highly evaluated it and took out their test data and traditional GPRS Compared with CDMA networks, the advantages are quite obvious. Next, the EDGE network began to be tested in various cities and regions in the country, of course, excluding large cities such as Beijing and Shanghai, because these large cities tend to lag behind in the process of testing new technologies.

After nearly one year of experiment and inspection period, the EDGE network has been popularized in many cities in China. Many users will be surprised to find that the E symbol is displayed on their mobile phones, which represents EDGE.

After several years of development, China Mobile's EDGE network has basically covered the whole country, and only some remote areas cannot be accessed; China Unicom has covered the whole country.