Technical optimization solution for 3G Local Access Network

After studying the technical optimization solution of 3G local access network for a long time, I would like to share with you that you will certainly have a lot of gains after reading this article. I hope this article will teach you more things. The 3G local access network bearer scheme should be selected from the operational and technical aspects.

From the operational perspective, it mainly depends on factors such as business needs, construction costs, O & M costs, and the status of network resources. From the technical perspective, it mainly depends on technological development trends, technical characteristics, technological maturity, and business characteristics carried by the network. Currently, there are two types of bearer solutions for 3G local access networks: one is the MSTP-based optimization solution and the other is the segmented transmission solution, it is also divided into enhanced Ethernet, Packet Transport Network (PTN), IP/MPLS and other different technical routes.

MSTP optimization technical solution

MSTP (Multi Service Transport Plateform) is a new generation of transmission system platform. It makes full use of SDH technology to provide protection and recovery capabilities for businesses and reduce latency, the network service transfer layer is improved to provide access, convergence, and transmission capabilities for various businesses and protocols with different particles in the SDH frame format. At present, MSTP has been widely deployed for carrying 2G mobile services. Considering the actual situation of protecting existing network investment and 2G, 3G base station co-location, in the initial phase of 3G construction, when the data traffic is relatively small, you can embed the EoS (Ethernet over SDH) board in the MSTP System to directly perform layer-2 switching of data frames from the Ethernet interface, it is encapsulated by the Green (Generic Framing Procedure) protocol, mapped to the VC container, and then added the overhead. Finally, the frame of the STM-N is formed to carry the Ethernet service.

MSTP technology is used to build a 3G local access network. Due to its rigid pipeline characteristics and sudden and uncertain data business characteristics, it will bring huge bandwidth pressure to the transport network access layer and convergence layer, therefore, bandwidth convergence and convergence are required to improve the bandwidth utilization of the transmission network. You can consider the following three solutions to achieve convergence and convergence of bandwidth:

Level 1 aggregation + passthrough Mode

This scheme configures 3G local access network Ethernet passthrough disks on the base station side to directly transparently transmit the base station services to core nodes for aggregation. The advantage is that the business configuration is simple, it is easy to handle the circuit adjustment problems caused by base station load sharing and ownership adjustment. The disadvantage is that the Backbone Node's EoS aggregation ratio is high and the subsequent expansion pressure is high.

Secondary aggregation + convergence Mode

This solution implements secondary aggregation on the aggregation node and the Backbone Node respectively. The advantage is that the core layer EoS board aggregation and configuration pressure are reduced, and the aggregation layer can achieve bandwidth convergence and save bandwidth; the disadvantage is that the business configuration is complex, especially when the base station changes the ownership of RNC, and cannot meet the backbone and convergence layer dual-node attribution network requirements.

Embedded RPR + EoS passthrough

This scheme uses the EoS passthrough mode in the access layer to transparently transmit the services of the base station to the aggregation node, and uses the MSTP ring structure embedded with RPR in the aggregation layer, the advantage is that the rpr mac layer can be used for classification of service levels and reuse of statistics to achieve bandwidth sharing and fair access. The disadvantage is that it cannot implement end-to-end service configuration, you need to configure EoS and RPR in segments. In addition, layer-3 devices can be added between the MSTP network and RNC to terminate the layer-2 network, reducing the pressure on RNC bandwidth convergence and VLAN processing; it can also be used to adjust the circuit of the base station to reduce the adjustment workload of the MSTP circuit. At the same time, it can provide more flexible connection protection with MSTP and RNC.

Technical Solution

With the introduction of new air interface technologies, such as high-speed downlink data group access (HSDPA) and multi-input/multi-output (MIMO) antennas, the speed of mobile data services will be greatly improved, if MSTP technology is used, the transmission cost per bit will be too high due to the following features: TDM Circuit Switching kernel (not suitable for statistics reuse of a large number of mobile data businesses ). Rigid pipelines (the adaptive particles for grouping businesses are VC-12/3/4, the bandwidth utilization rate of bearer burst businesses is low, and the bandwidth adjustment granularity is too coarse, lack of elasticity ). Poor scalability (when the FE bandwidth demand of the base station increases significantly, the single-board VC aggregation and L2 switching have poor scalability and inflexible adjustment issues ), the service quality assurance mechanism is simple (it is difficult to provide Differentiated Services ). Therefore, it is necessary to introduce grouping technology with efficient statistics reuse to reduce the transmission cost per bit and improve the transmission efficiency of the network. Currently, mainstream packet bearer technologies include enhanced Ethernet, PTN, and IP/MPLS technologies.