In the future, mobile network operators will have to provide broadband data rates to an increasing number of users with lowest cost per bit and probably as flat rates, such as is known from fixed network providers. Inter-cell interference is the most limiting factor in current cellular radio networks, which means that any type of practical feasible interference mitigation will be of highest importance to tackle the expected 100-fold traffic challenge. Cooperation is the only means known to really overcome interference and is therefore a very likely candidate for integration into an enhanced LTE system. In the beginning of 2008, the first 3GPP LTE release 8 standards emerged, defining most of its fundamental parameters and procedures. In the context of next-generation mobile networks (NGMNs) and the LTE SAE trial initiative (LSTI), the single-link performance of LTE for 2 × 2 MIMO systems has been validated based on existing real-time hardware (HW). Outdoor multiuser measurement campaigns for single sites are more than proven the high benefits of MIMO and OFDMA, providing a user data rate of more than 100 Mb/s in a significant part of the radio cell.
The logical next step will be the optimization of the multicell network, which includes the transmission from more than one sector as well as from more than one site. As known very well, cellular radio systems in general (and specifically LTE) suffer significantly from interference in urban areas, reducing overall spectral efficiency from an ideal of about 10 to a few bits per second per hertz per cell. That’s why many network elements and associated parameters are manually configured. Planning, commissioning, configuration, integration and management of these parameters are essential for efficient and reliable network operation; however, the associated operations costs are significant. Specialized expertise must be maintained to tune these network parameters, and the existing manual process is time-consuming and potentially error-prone. In addition, this manual tuning process inherently results in comparatively long delays in updating values in response to the often rapidly changing network topologies and operating conditions, resulting in sub-optimal network performance.
SON provides various valuable functions including:
- Self Healing: the self healing concept includes the necessary software and hardware upgrades to prevent disruptive problems from arising.
- Self Optimization: The self optimization concept auto-tune the network setting by utilizing of measurements and performance indicators collected by the User Equipments (UEs) and the base stations. This function occurs when the cell is not batted or in the operational state. The operational state is the state where the Radio Frequency (RF) interface is commercially active.
- Self Planning: The self planning is derivation of the setting for new network node, including the selection of the site location and the specification of the hardware configuration, but exclude site acquisition.
- Self Deployment: Self deployment includes all procedures to bring new nodes to commercial operation, expect for the ones included in the self-planning category. It also involves preparation, installation, authentication and delivery of a status report of a new network node.
The current commercial and standardization efforts are focused on the introduction of SON for LTE networks; there are some benefits from installing SON in GSM/GPRS/EDGE and UMTS/HSPA RATs. SON has multi technology concepts in both LTE and current RAT, which allow the operators to completely transform and streamline their operations from the current networks to the new additional LTE network layer, which also harmonizes the whole network management approach and boost operational efficiency.
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