Cloud Radio Overview

Cloud Radio is a performance enhancement solution for LTE network. This solution could effectively mitigate the inter-cell interference and significantly improve the performance of LTE networks, especially for the cell-edge performance which has a great influence on user experience. This solution provides high-speed and seamless mobile broadband access experience for users.

The key technology of Cloud Radio solution is cloud coordination, which introduces differentiated innovative technologies, such as Coordinated Multi-Point (CoMP) Lite and dynamic CoMP, on the basis of CoMP solution. Therefore, this solution can overcome the application limitations of standard CoMP technologies, and can implement inter-site, physical-layer coordination based on the existing PTN, microwave, and other bearer networks.

Source of Innovation
Serious Inter-Cell Interference in LTE Networks and Restrictions on CoMP Solutions
Compared with 2G and 3G networks, the inter-cell interference in LTE network becomes more severe. The reasons are:

Co-frequency networking: Compared with the Frequency Division Multiplexing (FDM) GSM technologies and Code Division Multiplexing (CDM) WCDMA technologies, the OFDMA-based LTE technologies have no inborn mechanisms for inter-cell interference mitigation. In addition, due to scarce and expensive spectrum, normally LTE uses co-frequency networking, which makes the interference problem worse.
 

Dense cells: LTE networks aims for high-speed data access, it should give more consideration to satisfied bandwidth than signal coverage. Therefore, LTE sites will become much denser than 3G (only several hundred meters or even less in dense urban areas), which increases inter-cell interference and lowers cell performance.
 

Heterogeneous networking: The heterogeneous network has become a major solution for LTE capacity enhancement. Small cells often use the same frequencies as macro base stations, it does improve capacity while introduce interference at the same time. LTE network performance, especially the cell-edge performance, depends greatly on interference mitigation and elimination technologies.
 
The interference in large-scale commercial LTE networks is more serious than expected, while standard CoMP solutions are limited by mobile backhaul conditions.
Insufficient attentions on interference: The interference in LTE network is not obvious when the traffic is light. With the scale application of LTE service, the rapid growth of LTE traffic will dramatically increase the interference and worsen system performance, and the Inter-Cell Interference Coordination (ICIC) technology is not enough to solve the complicated interference problems.
 

Limitation of standard CoMP applications: The commercial LTE Networks use diversity bearer networks, transmission bandwidth start from tens of Mbps and end with fiber-to-the-site (tens of Gbps). Standard CoMP solutions can achieve the best coordination performance in fiber-to-site scenario, but this requirement is much higher than the performance of existing bearer networks. Therefore, Stand CoMP solutions can only be used in very limited scenarios.
　 

 Inter-Site Coordination Is More Important for Improving User Experience
Intra-site coordination is not enough for seamless moving user experience.
Standard CoMP solutions have high requirements on the bandwidth and delay performance of bearer network, normally is only implemented inside a site. Intra-site coordination mainly improves the performance of a single base station; there are still lots of performance troughs among multiple sites, so user experience fluctuates greatly when users move across the network.

 Inter-site coordination is more important than intra-site coordination.
Cell-edge performance has obvious affects on network KPIs, such as the access success rate and the Dropped-Call Rate (DCR) during handover. Therefore we should focus on inter-site (cell-edge) coordination. A small improvement of the cell-edge performance will bring significant changes in user experience, while further improvement of cell-center performance cannot evidently enhance user experience.

Highlights and Benefits of Cloud Radio

As a leading vendor of wireless network solution, TENSUN launched the innovative Cloud Radio solution at the Mobile World Congress held in Barcelona in February 2013.

Cloud Radio solution breaks the limitations of standard CoMP technologies on mobile bearer networks. For example, the CoMP Lite technology is used to lower the requirements for bandwidth and delay, and makes the advanced technologies available in popular PTN, IP-RAN, and microwave bearer networks, significantly reducing mobile operators' investment in 4G networks.

With TENSUN's innovative Cloud Radio solution, operators can solve LTE network interference problems with lower costs and provide users with beyond 4G access performance.

 
Flexible Adaptation to Existing Mobile Bearer Networks, Lowering LTE Network Deployment Costs

Popularization of advanced coordination technologies: By using the innovative CoMP Lite, scheduling in advance, Joint Transmission (JT), and Coordinated Scheduling (CT) technologies, Cloud Radio solution can significantly reduce the requirements for bandwidth and delay of mobile bearer networks, and frees CoMP from intra-site and intra-BBU-pool scenarios. I.e. Cloud Radio technologies will no longer depend on dark fibers, and are adaptable to multiple existing IP bearer networks.
 

Dynamic adaptation to mobile bearer conditions: Cloud Radio solution supports IP-based coordination data exchanging, and is adaptable to mobile network conditions through multi-level cloud coordination mechanisms. Cloud Radio solution can help carriers deploy the most suitable coordination solutions according to the available bandwidth of microwave, MPLS, and PTN bearer networks. In addition, the elastic bandwidth mechanism allows for reliable operation of cloud coordination technologies even in case of sharp fluctuations of bearer network performance. Therefore, Cloud Radio solution has a higher environmental adaptability compared with standard solutions.
 

The highest coordination profit with Lowest bearer cost: TENSUN's adaptable cloud coordination technologies make possible independent LTE access network construction and bearer network upgrade, and can achieve the best wireless coordination performance with available bearer resources in any stage. Therefore, operators do not need to invest heavily in bearer network construction in the initial stage of LTE deployment but can use the existing bearer networks to make more profit from performance improvement. With TENSUN's Cloud Radio solution, operators can achieve the coordination performance in PTN bearer networks similar to that achieved in dark fiber bearer conditions.