EREG (Enhanced resource-element group)

Last updated on Apr 4, 2023

Enhanced resource-element group (EREG) is a concept used in 5G wireless communication networks to efficiently allocate and manage resources for data transmission. EREG is an extension of the resource-element group (REG) used in earlier wireless communication standards such as LTE. In this article, we will discuss in detail what EREG is, its features, benefits, and how it works in 5G networks.

Resource Element Group (REG)

Before delving into the concept of EREG, it is essential to understand what a resource-element group (REG) is. In wireless communication, a REG is a set of contiguous resource elements (REs) in the frequency domain that is allocated to a user for transmission. REs are the smallest unit of resources in the frequency domain, which can carry one symbol of information in a single subcarrier. The number of REs in an REG depends on the size of the bandwidth allocated to the user. In the LTE system, an REG consists of 12 consecutive subcarriers and 7 consecutive OFDM symbols, making up a total of 84 REs.

Enhanced Resource Element Group (EREG)

EREG is a new concept introduced in 5G networks to enhance the efficiency of resource allocation and utilization. EREG extends the concept of REG in several ways, making it more flexible and adaptable to various scenarios. One of the main features of EREG is that it allows for non-contiguous allocation of resources in the frequency domain, which is not possible with the REG concept.

EREG is defined by the 3GPP standard as a set of resource blocks (RBs) that can be allocated to a user for transmission. Each RB consists of 12 consecutive subcarriers and one slot in the time domain, making up a total of 14 REs. Unlike the LTE system, where the number of REs in an REG is fixed at 84, the number of REs in an EREG can vary depending on the size of the allocated RBs. For example, an EREG with four RBs would have a total of 56 REs.

EREG offers several benefits over the REG concept. Firstly, it allows for more efficient use of the available spectrum. Non-contiguous allocation of resources in the frequency domain means that unused spectrum can be utilized for other purposes, such as providing services to other users. Secondly, EREG provides greater flexibility in resource allocation. The number of RBs allocated to a user can vary depending on the user's needs, which makes it easier to adjust the resource allocation based on the traffic load. Finally, EREG enables more efficient scheduling and resource allocation in multi-user scenarios, which is critical in 5G networks.

How EREG works

EREG works by dividing the available spectrum into RBs and allocating them to users based on their requirements. The allocation process involves several steps, including RB aggregation, modulation, coding, and mapping.

The first step in the allocation process is RB aggregation. RB aggregation involves combining multiple RBs into a single EREG to increase the bandwidth allocated to the user. RB aggregation can be performed in either the time or frequency domain, depending on the user's requirements. For example, if a user requires a high data rate, RB aggregation can be performed in the time domain to increase the number of slots allocated to the user.

The next step in the allocation process is modulation and coding. Modulation and coding involve encoding the user's data using a specific modulation scheme and channel coding rate. The modulation scheme and channel coding rate are selected based on the user's signal quality and the amount of interference present in the channel. The goal of modulation and coding is to maximize the data rate while minimizing the error rate.

Once the data has been modulated and encoded, it is mapped onto the allocated RBs. Mapping involves assigning the modulated and encoded data to specific REs within the allocated RBs. The mapping process is essential for ensuring that the data is transmitted efficiently and that there is no interference between different users. EREG provides greater flexibility in mapping compared to the REG concept since it allows for non-contiguous allocation of REs in the frequency domain.

After the data has been mapped onto the allocated REs, it is transmitted using the assigned resources. The transmission process involves sending the modulated and encoded data over the air interface using the allocated resources. The transmitted data is then received by the receiving device, where it is demodulated and decoded to recover the original data.

Applications of EREG

EREG has several applications in 5G networks, including:

High-speed data transmission: EREG allows for high-speed data transmission by aggregating multiple RBs to increase the available bandwidth.
Low-latency communication: EREG enables low-latency communication by allowing for efficient scheduling and resource allocation in multi-user scenarios.
Massive machine-type communication (mMTC): EREG is well suited for mMTC applications, which involve the transmission of small packets of data from a large number of devices. EREG's flexibility in resource allocation allows for efficient use of the available spectrum and efficient scheduling of resources.
Ultra-reliable low-latency communication (URLLC): EREG is also suitable for URLLC applications, which require reliable and low-latency communication. EREG's flexibility in resource allocation enables efficient scheduling and resource allocation to ensure reliable communication.

Conclusion

EREG is an essential concept in 5G networks that enhances the efficiency of resource allocation and utilization. EREG provides greater flexibility and adaptability compared to the REG concept, enabling efficient use of the available spectrum and efficient scheduling and resource allocation in multi-user scenarios. EREG has several applications in 5G networks, including high-speed data transmission, low-latency communication, mMTC, and URLLC. As 5G networks continue to evolve, EREG will play a critical role in ensuring efficient and reliable communication.