2G/3G switching and business hosting allocation strategy

Overview of 1.2G/3G Network Wireless resource planning

GSM network is the most widely used mobile communication network in 2G network, and has more than 1 billion GSM users in more than 200 countries and regions. China Mobile is currently the world's largest GSM operator, with close to 300 million user capacity of 2G network resources and perfect coverage, 3G network construction in the initial period, 3G network may be limited to continuous coverage of urban areas, how to use the existing 2G network of China Mobile for 3G users to provide seamless business coverage, How to solve the interconnection of two networks/coordinated development, to provide users with excellent business quality is a key problem of 3G network construction. Therefore, it is necessary to analyze and verify the possible networking mode between 2G/3G, the key technologies related to the coexistence of 2G/3G network, such as network selection strategy, community selection and re-election, handoff strategy, etc., to provide valuable experience for the construction of 3G network in the future.

2. All kinds of business in 2G/3G network coexistence of handoff strategy discussion

2.1 Basic voice service switching strategy

Voice business belongs to the Conversation class business, 2G system can fully support, the effect is slightly worse than 3G, but the user is completely acceptable. Therefore, in the early 3G network construction, the opening of 3G to 2G voice service switching to make full use of 2G network resources to make up for the early 3G voice coverage and capacity deficiencies. (Computer science)

The switching quality of this kind of service and the subjective feeling of switching off the user are obvious, and the success rate is very important. Therefore, it is not recommended to open reverse switching (2G to 3G voice switching), to avoid overlapping overlapping coverage area of the ping-pong switch resulting in a decline in the success rate. If the user returns to the 3G coverage area, this call is still done in the 2G system. Until the end of the call, through the cell re-election and other ways to return to the 3G network.

Discussion on reducing quality switching of 2.2 videophone

Videophone also belongs to the conversation class business, but 2G system cannot support this kind of business. When switching, you can consider transforming this kind of business into AMR business to ensure the user's basic voice call.

The release of cs64k business is required in the Rabreleaserequest message sent to CN by the RNC. CN received the message found this business for cs64k, then issued a message will CS64 modified to AMR12.2 business, CN needs to be called at the same time modify. The RNC modifies the current business to AMR through the RB reconfiguration process, and can then initiate a 3G to 2G switch based on the AMR business. When a user returns to the 3G coverage area, it is also recommended that the 2G to 3G switch not be opened, allowing the user to complete this call on the 2G network.

2.3 Switching strategies for streaming media services

The hosting network distinguishes between high-speed and low-speed services by negotiation type and negotiation rate. If the negotiation type is a stream class, and the negotiation rate is higher than the rate threshold of the system setting, it is considered to be a high speed streaming business, because the 2G system can only support the low speed PS service and cannot support the high-speed streaming business with guaranteed rate, so this kind of service does not switch 3G to 2G In the actual network operation process, the operator may provide the service to provide the distribution area (that is, 3G of coverage area), so that the designated area occurs on TV on demand, the user can also understand.

If the negotiation type is a background class and an interaction class, or if the negotiation type is a stream class but the negotiation rate is lower than the threshold of the system setting, it is considered that the 2G system may be able to support this kind of business and be processed according to the interaction class/background class business. For the flow class business, because 2G can support the lower rate of streaming business, it can be implemented by reducing QoS.

2.4 Switching strategies for interactive class and background class services

This kind of business because has the characteristic which the rate is small or can endure the small rate bandwidth, may switch it to the 2G system. It is recommended to open 2G to 3G switch from 2G system back to 3G system to gain a better user experience. Because GPRS can support background class and interactive class business, from 2G back to 3G system can basically revert to the original QoS.

3.2G/3G Network Service load allocation strategy

3.12G/3G Networking Scheme

With 2G and 3G networks coexisting, there are three alternative networking scenarios

For the above three kinds of schemes, considering their pros and cons synthetically, it is suggested that the 3G network should be constructed with scheme two. For the initial stage of the network, 3G coverage is small, only need to upgrade the 2G network within the scope of 2G, 3G between the roaming, in order to minimize the risk of the case to maximize the quality of the 3G User Service.

3.2 Business hosting allocation policies based on user-level

Access Strategy

After the completion of the 3G network, 3G users can access 3G or 2G network, and 2G users can only access the 2G network, can not access the 3G network.

For scenario two, in the 2G, 3G of the total coverage area, to prohibit the use of dual-mode terminal 2G users try to login 3G network, so as to prevent the 3G network to bring some additional signaling interaction and load, this can be through the core network in the 3G network to update the location of the request to reject the UE to achieve.

Network Selection Policy

3G users can have a variety of network selection methods, respectively, preferably 3G network, preferably 2G network and no priority. It is recommended that 3G users should choose the way to optimize the 3G network. To achieve this way, for 2G, 3G with PLMN situation, can be designated in the USIM card 3G priority access to the wireless access technology to achieve, but for the case of PLMN, as long as the USIM card designated HPLMN as 3G PLMN can.

If a preferred 2G network or no priority is used, 3G users may reside in the 2G network for a long time at the present 2G coverage is good. When the launch of the business, 2G system to determine that the 3G unique business situation needs to initiate a directional retry, in order to switch the phone to 3G network, to maintain the normal business access. The adoption of this process, whether from the point of view of the Agreement or the implementation of the manufacturers are not conclusive, the need for the current network 2G system needs to make a larger upgrade, and increase the number of 2G and 3G signaling interaction, increase the load of 2G system, to achieve greater risk. At the same time, the use of this method will enable users from the terminal network or antenna identification of their own long time in the 2G network, to the user caused by the misunderstanding of 3G network coverage.

The use of the preferred 3G network can make 3G users in the 3G coverage area always resides in the 3G network, to reduce the additional load to the 2G network, when the terminal leaves the 3G coverage area, you can through the system switching or cell re-election to the 2G network to ensure continuity of business. In this way, in the initial stage of network operation, the network capacity is sufficient, fully feasible; As for the middle and late period, the user grows rapidly, the capacity is limited, the operator may take the increase carrier frequency, uses the transmit diversity and so on the technology to increase the corresponding capacity. Even when the capacity is unable to increase, can also use the access to redirect retry, load balance between the system or the measurement of system switching between the AMR12.2K and PS Low-speed Services can be assumed 2G system to 2G system, to ensure that the 3G system service quality and smooth operation.

3.3 Business-based balancing strategy

The strategy of district re-election

3G based users should be able to reside in the 3G network as much as possible, enjoy the 3G network to provide quality service considerations. The 3G Network load is normal, as long as the quality of the 3G network to meet the minimum business rate needs can reside. For the same reason, in the 2G network 3G cell re-election threshold should be less than the 2G cell re-election threshold, so that the 3G users residing in the 2G network can be more easily returned to the 3G network. When the 3G Network load is high, the system needs to automatically adjust the threshold of the cell selection, the selection threshold of the 3G cell should be adjusted, so that some 3G users select to 2G network to reduce the load of 3G network.

3G Network Load is too large, the RNC will use the following order to reduce network load, spin down (first PS business after CS business), reduce service quality (increase business bler), with coverage frequency blind, soft switch state of the strong cut, the system switch between. When the 3G network overload, the new Access AMR service will try to redirect to the 2G network.

System switching policies

For operators operating WCDMA system and GSM system simultaneously, it is necessary to realize the seamless roaming between WCDMA system and GSM system, especially in the process of call. But in the call process between the system switching to the user's business is limited, that is, only WCDMA system and GSM system can support the business. WCDMA system can provide more business than GSM system, such as Videophone, ps384k business GSM system can not provide, so in WCDMA to GSM switching to be limited by the business.

When the WCDMA system load is high, it is necessary to carry out the load balance between the system and the 2G system, and the new Access user can be assigned to the GSM system through directional retry, or the user who keeps the call in the 3G system is switched to the GSM system.

In the case of WCDMA cell and GSM community, the HCS structure (layered Community structure) is formed, in order to avoid the frequent switching operation of fast moving users and its impact on other users in WCDMA community, WCDMA system can be switched to cover the larger GSM community (such as GSM900 community).

4. ZTE Communication 2G/3G Fusion solution

1.3G MSC Auto Fit 2G MSC

At this stage, there are still many problems in the switch between 2g/2.5g and 3G. 3GPP only makes the switch between the R99 version of the 3g/2g, so it is required to upgrade the original 2G network to R99 to support the switching between the systems. and upgrading the original network, for mobile operators is a huge risk. To solve the above problems, ZTE can take 3G MSC compatible with 2G of different manufacturers of MSC, the 2G of MSC to do the appropriate adaptation, so that 2G MSC can not upgrade, greatly reduce the operator in the initial stage of the network risk.

2. Smart Community Re-election

When the 3G Network load is high, ZTE WCDMA network can automatically adjust the selection threshold of the cell, appropriately adjust the selection threshold of 3G cell, so that some 3G users select to 2G network to reduce the load of 3G network. This process is performed automatically and is reversible according to the network load.

3. Load-based balance between systems

When the WCDMA system load is high and satisfies the condition of load balance between systems, if a user is connected to WCDMA system, ZTE's WCDMA system supports assigning it to the GSM system via directional retry. If the load of WCDMA system continues to increase and the load control condition is reached, the ZTE WCDMA system can keep the caller in the system and switch it to the GSM system to ensure the security of WCDMA system.

ZTE is currently the industry's most abundant mobile network products manufacturers, accumulated a large number of mobile network development experience, has formed WCDMA, GSM, CDMA2000, TD-SCDMA, PHS and other full network solutions. ZTE has carried out in-depth research on the service allocation, handoff and interference between 2G and 3G systems, completed the system analysis, simulation and testing work, and formed a complete 2g/3g fusion solution. ZTE is confident to work with Chinese operators to build a world-class 3G boutique network.