Enterprises are adopting a new multiple access technology to consider when looking for ways to increase the capacity of their 5G networks: beam-splitting multiple access.
Rather than allocating channels depending on frequency, BDMA uses beamforming and orthogonality to target subscribers and increase overall network efficiency. Let’s explore how this method works and explore the key BDMA features.
Multiple access and its importance
Multiple access is the basis of wireless communication systems. As the term suggests, this technology allows multiple users to share a finite radio spectrum simultaneously. Each user device can access the available bandwidth simultaneously without interfering with other user devices.
Previous generations of wireless communication technology used the following multiple access techniques:
- Code division multiple access.
- Frequency Division Multiple Access (FDMA).
- Time division multiple access.
5G has a unique set of multiple access technologies, including:
- Orthogonal FDMA (OFDMA).
- Single carrier FDMA.
- Non-orthogonal multiple access (NOMA).
- BDMA.
BDMA is the latest addition proposed by scientists at the Korea Advanced Institute of Science and Technology.
How does BDMA work?
BDMA works by assigning highly directional orthogonal beams to multiple mobile stations in a 5G network. Splits the base station antenna beam according to specific criteria and the location of the subscriber within the cell. BDMA uses a beamforming precoding strategy to improve internet connectivity and reduce interference.
BDMA is independent of frequency, time, and code constraints, allowing it to overcome the limitations of FDMA and orthogonal frequency division multiplexing (OFDM) in wireless communications. Within 5G networks, BDMA allows 5G networks to handle large numbers of mobile users while reducing multi-user interference. In other words, implementing BDMA allows 5G networks to more efficiently utilize spectrum capacity while increasing the number of channels.
Imagine a BDMA-compatible 5G network consisting of a base station and multiple mobile stations in a cell with a multi-user multiple-input multiple-output (MU-MIMO) array system.
The broadcast beam identifies the necessary information from the mobile station. The selected subscribers are identified by beamforming based on various criteria such as the direction of the mobile station and the degree of interference. Massive MIMO beams are converted to single-user MIMO beams for efficient communication. Highly directed beams reach multiple target subscribers based on client device location, speed, and orthogonality.
BDMA features
Below are some of the key BDMA features that may impact 5G networks.
MU-MIMO base station
BDMA base stations must support mmWave and implement MU-MIMO beamforming technology. A base station obtains information about mobile client devices within its cell. Select subscribers based on selection criteria. BDMA uses hybrid beamforming to transmit signals from a base station to multiple mobile users within a cell.
hybrid beamforming
BDMA relies on hybrid beamforming to increase 5G capacity. Hybrid transmitters combine the functionality of digital and analog beamforming. Each RF chain of hybrid transmitters is connected to the antenna array of the base station.
Beam characteristics
Beamforming is used to select the MU-MIMO beam at the base station. Each beam is different from the others and has a different direction, angle, and width depending on the subscriber’s location. MU-MIMO beams are converted into subsets for transmission. Each beam group communicates with selected subscriber devices.
Subscriber selection
Subscribers are selected on the basis of their inability to interfere with other devices in the cell. Different selection techniques compare the degree of independence between each user and her devices. BDMA uses mathematical vectors to measure the degree of independence of user devices within a cell.
precoding technology
Precoders are used to optimize the transmitted signal. BDMA uses various precoding techniques, such as zero forcing and orthogonal beamforming, to reduce interference and improve the efficiency of BDMA-compatible networks.
Beam schedule and transmission
The base station schedules and assigns beams to selected subscribers depending on the subscriber’s location and available throughput. The beam is further divided into subsets, each focusing on an individual subscriber within the cell. Using this approach, a beam can serve multiple subscribers within a cell, all of whom can uplink and downlink information after scheduling begins.
Advantages of BDMA
Here are some of the benefits of BDMA:
- Improved signal quality and high signal-to-noise ratio even in areas with high interference or low signal strength.
- Reducing costs associated with power consumption.
- Safe and secure as it is less susceptible to interference.
- Ability to focus antenna beams on areas of highest demand and away from areas of lower demand.
- Ability to drop calls for devices with high interference in situations where there are a large number of subscribers in the cell.
Limits of BDMA
Here are some limitations related to BDMA:
- BDMA is relatively new and can be complex to implement. Fewer compatible devices and base stations support BDMA.
- For effective communication, your subscribers need to be within your direct line of sight.
- BDMA requires one antenna per user for simultaneous data transmission, reducing its ability to support large numbers of subscribers.
conclusion
BDMA provides high data rates to mobile subscribers and even higher data rates to fixed subscribers in cells where interference is negligible. Currently, the majority of 5G networks rely on OFDM and OFDMA, but more networks may start supporting BDMA as well.
Venus Kohli is an electronics and telecommunications engineer who completed her engineering degree from Bharati Vidyapeeth College of Engineering, University of Mumbai in 2019. Kohli works as a technical she writer in electronics, electrical, networking, and various other technology categories.
