BLER stands for Block Error Rate, which is a measure of the quality of the radio link between the user equipment (UE) and the base station (BS) in a cellular network. BLER is defined as the ratio of the number of erroneous blocks to the total number of transmitted blocks in a given time interval. A block is a unit of data that is encoded and modulated before transmission. A block is considered erroneous if it fails the cyclic redundancy check (CRC) at the receiver side.
BLER is an important parameter for cellular radio access network planning and optimization, because it reflects the performance and reliability of the radio interface. BLER affects the user experience, the network capacity, and the resource utilization. For example:
• BLER affects the user experience, because it determines the quality of service (QoS) and the data rate that can be achieved by the UE. A high BLER means that more blocks are corrupted and need to be retransmitted, which reduces the effective throughput and increases the delay. A low BLER means that more blocks are correctly received, which increases the data rate and improves the QoS. Different applications have different BLER requirements, depending on their sensitivity to errors and delays. For example, voice and video calls require a low BLER (less than 1%) to ensure good speech and video quality, while web browsing and file downloading can tolerate a higher BLER (up to 10%) without much degradation.
• BLER affects the network capacity, because it determines the number of users that can be supported by the network and the spectral efficiency that can be achieved. A high BLER means that more radio resources are wasted on retransmissions, which reduces the network capacity and the spectral efficiency. A low BLER means that fewer radio resources are needed for transmissions, which increases the network capacity and the spectral efficiency. The network capacity and the spectral efficiency depend on the modulation and coding scheme (MCS) that is used for transmissions. A higher MCS provides a higher data rate, but also requires a higher signal-to-noise ratio (SNR) and a lower BLER. A lower MCS provides a lower data rate, but also requires a lower SNR and a higher BLER. The optimal MCS depends on the channel conditions and the traffic demand.
• BLER affects the resource utilization, because it determines the power consumption and the interference level in the network. A high BLER means that more power is needed to transmit and receive blocks, which increases the power consumption and the interference level. A low BLER means that less power is needed to transmit and receive blocks, which decreases the power consumption and the interference level. The power consumption and the interference level depend on the power control mechanism that is used to adjust the transmission power of the UE and the BS. The power control mechanism aims to achieve a target BLER that balances the trade-off between power efficiency and interference management.
Therefore, BLER is a significant parameter for cellular radio access network planning and optimization, and it should be carefully monitored and controlled to ensure the optimal performance and operation of the network.