CDMA expansion scheme based on LTE network architecture

With the continuous development and maturity of LTE, the evolution of CDMA to LTE has become an inevitable trend. However, the evolution of networks is a long-term process. From the evolution of LTE Networks to the full migration of CDMA users, the two networks need to coexist for many years. How can we make the evolution of CDMA to LTE smoother, lower evolution costs, and faster LTE deployment? With these questions, this article will discuss how to consider Evolution and Development to LTE in the expansion of CDMA, so as to prepare for the evolution of LTE in the development phase of CDMA.

I. Comparison between LTE and CDMA

2. Coverage comparison

In the same frequency band, the coverage level of LTE and CDMA is basically the same. However, in the initial phase of LTE network construction, there is generally no redundant spectrum available for CDMA for LTE, and the new spectrum applied for by LTE is generally relatively high. Taking 2.1G for example, to achieve an edge rate equivalent to that of DORA (downstream 307.2/upstream 76.8 kbps), the number of sites in LTE 2.1G is more than twice that of cdma m, the gap between the number of sites is basically the same as the average site spacing data of the current commercial network.

Ii. Preparation of spectrum resources

As data services develop rapidly, frequency resources may become bottlenecks in network development. The more spectrum resources the operator has, the larger the network capacity, the better the user experience. Therefore, for the evolution of CDMA networks to LTE Networks,

1. We recommend that you apply for new frequency resources. Many CDMA networks only have 5 Mbit/s/10 Mbit/s of spectrum resources. It is unrealistic to free up a portion of the intense CDMA spectrum resources for LTE Networks.

2. We recommend that you apply for a low frequency spectrum whenever possible. Generally, high-frequency band bandwidth is suitable for low-frequency segments. The lower the frequency band, the better the coverage, and the lower frequency band can greatly reduce the network construction cost. Considering the coverage and capacity factors, it is best to deploy LTE in multiple frequency bands and try to use ipvm ~ in the suburbs ~ 800 M, M ~ 2.6 GHz.

3. Site Preparation

Site Resources are very important resources for wireless network construction, and have the greatest impact on network construction costs and construction periods.

1. website preparation covering restricted scenarios

For areas with limited CDMA coverage, LTE coverage will be more severe in the future. Deploying sites in this region in advance not only improves the coverage of the current CDMA network, but also improves the user experience, and can fully meet the site requirements for LTE network construction in the future.

Taking the urban area as an example, sites in areas with poor coverage are usually difficult to obtain, and indoor coverage is difficult and costly. In this case, we recommend the HetNet networking solution. HetNet has various networking forms and flexible network structures. It is particularly suitable for areas that cover blind spots, capacity hotspots, and sites that are difficult to obtain. It is the development trend of the future network.

HetNet Network Architecture Reference:

For outdoor coverage, if the site is difficult to obtain, you can use the Micro station or the outdoor Pico Station to supplement the blind, use the pole and lamp pole to build a low station, and blind the coverage blind spots.

For indoor coverage, if the DAS is difficult to deploy or the deployment cost is high, you can use LPN nodes such as Pico for indoor coverage. Pico has obvious advantages in covering small and medium buildings.

HetNet has the advantages of flexible networking and easy deployment, but its relatively complex network structure also brings some difficulties:

1) How to precisely locate the weak coverage area. Currently, the most advanced method is to use the traffic map tool to analyze the massive amount of User call information on the current network. Combined with the map, you can accurately analyze the geographical location of weak coverage and traffic hotspot areas.

2) how to plan and optimize the HetNet network. The HetNet network planning and optimization of the macro-cell network structure is more complex. If macro-micro networks can be used for same-frequency networking, interference control will be the focus, requiring very accurate site selection, careful parameter planning and power control. You can also use a different-frequency networking, so that the terminal resident policy and the abnormal-frequency switching will be the focus. You can use a different-frequency-first resident policy so that the user will first stay on different frequent points, in order to achieve the effect of capacity shunting or coverage blind population, and the HDC scheme can be used for switching, to improve the success rate and user experience of different frequency switching.

2. Site Preparation in scenarios with limited capacity

For scenarios with limited capacity, we recommend the following solutions to increase the number of carriers without frequent resources:

1) New Technology for Capacity Improvement. For DO, you can use DORB and DO Advanced to improve network throughput and single user experience. For 1x, the new technology 4GV and 1x Advanced can greatly increase the 1x network capacity, and the 1x frequency can be saved for DO. This solution is cost-effective. You only need to upgrade the software, and some technologies need to use new channel processing boards. The disadvantage is that some features require terminal support. When the proportion of terminals that support new technologies is relatively small at the beginning of the upgrade, the increase of new technologies is not obvious, but as the proportion of new terminals increases, the advantages of new technologies will be apparent.

2) split the slice. Split one slice into two slice. In theory, the capacity after splitting is twice that before splitting, but due to increased interference and other factors, generally, the size after splitting is 1.6-1.8 times that before splitting. The Slice splitting method is cost-effective, the network construction speed is fast, and the Capacity improvement is also obvious. Due to the network topology changes caused by splitting, You need to invest more in network optimization.

3) add sites. Adding Sites includes adding macro sites, adding HetNet microsites, building indoor coverage systems and WLAN. For more information about the HetNet network, see the previous section.

Iv. Preparation of evolution capability

In addition to preparations for sites and spectrum resources, it is worth considering how CDMA networks will evolve to LTE Networks more smoothly, quickly, and at a lower cost in the future. In terms of evolution capabilities, we will focus on the following:

1. Preparation of Base Station Equipment

To build an LTE network based on a CDMA network, there are generally three solutions to prepare Base Station Equipment: Creating a New LTE base station; replacing the original CDMA base station with a dual-mode base station supporting both CDMA and LTE; add a small number of boards and upgrade software based on the CDMA base station hardware supporting LTE.

The third solution is the best in terms of cost and evolution speed. However, for new sites and old sites that need to be updated, it is best to directly select CDMA/LTE dual-mode base stations. Dual-mode base stations have great advantages in terms of equipment costs, space occupation, and unified maintenance. They are the mainstream solutions for Multi-standard coexistence of network evolution in the future.

2. Tianji and transmission preparation

The cost, installation space, and tower load-bearing of Tianji are important considerations. When creating or transforming a CDMA base station, consider the future construction of LTE. You can select dual-band antennas, multi-frequency antennas, and Broadband Antennas to save the construction cost and installation space of the next LTE antenna.

High throughput of LTE base stations and high transmission capacity requirements. Generally, the average throughput of a single sector is above 17 Mbps at 10 MHz bandwidth. Therefore, during the CDMA network transmission resizing, construction, or leasing process, it is best to consider the transmission requirements of LTE in advance to facilitate the rapid construction of LTE Networks in the future.