Using 5G/WiFi 6 to illustrate the structure and benefits of cross-domain SEPs

“Cross-domain SEPs can maximize commercialization potential because they can be made non-exclusive across multiple patent pools, thereby generating more revenue and improving availability.”

In today’s context, cross-domain standards essential patents (SEPs) refer to patents essential to two or more different domains that have distinct standards developed by different standards organizations (SSOs). The concept was born out of the idea that, despite the difference in standards, the domains are based on similar core technologies. Thus, patents essential to common core technologies will in turn be essential to both domains and, therefore, can be called cross-domain SEPs.

5G and WiFi 6

Standardized by 3GPP (3rd Generation Partnership Project) in version 15, 5G is a fifth generation extended wireless cellular technology. It aims to deliver high data speeds, ultra-low latency, massive network capacity, increased availability, high performance, and improved efficiency by connecting industries and delivering new user experiences.

Originally known as IEEE 802.11ax, Wi-Fi 6 was standardized by the IEEE (Institute of Electrical and Electronics Engineers) in 2020 and later named Wi-Fi 6 by the Wi-Fi Alliance. Sixth-generation WLAN (Wireless Local Area Network) technology delivers high throughput, low latency, and high capacity. Wi-Fi 6 uses a variety of wireless techniques and combines them in a way that achieves a significant advance over previous standards while maintaining backward compatibility with previous Wi-Fi generations.

Regardless of the differences between 5G and Wi-Fi 6, the two areas have a common ground in technologies such as orthogonal frequency division multiple access (OFDMA), multi-user (MU)-multiple- input, multiple-output (MIMO), beamforming, and spatial multiplexing. Both leverage carrier aggregation with OFDMA as a primary channel access scheme to provide greater capacity to users through increased spectrum agility.

OFDMA is a technique that enables MU transmissions such that an access point can simultaneously transmit and receive information, to and from multiple users, in the same downlink/uplink. It is a modulation scheme that is equivalent to a multi-user version of OFDM. Like the approach inherited from OFDM, where all bandwidth is divided into several subcarriers, OFDMA allocates groups of these subcarriers, called resource units (RUs), which can be assigned individually.

Wi-Fi 6 and 5G are both based on OFDMA technology, derived from the Long-Term-Evolution (LTE) standard. While OFDMA support for uplink and downlink in Wi-Fi 6 is a first in Wi-Fi standards and introduced subcarriers for simultaneous transmission of user data, it is already in use in cellular networks.

Additionally, Wi-Fi 6 has an individual target wake-up time (TWT) based on OFDMA. TWT allows each device to request its own precise wake-up time and recurring service period (SP). The access point honoring this request can aggregate large groups of such requests into far fewer triggered TXOPs (Transmission Opportunities), resulting in more efficient, deterministic, and contention-free channel access performance. This is analogous to the cellular paging or 5G access channel structure having a similar dual effect of contention/loss reduction and STA (station) power savings.

MIMO allows data transfer over multiple antennas to take advantage of “multipath propagation”, a technique for increasing the transmission rate by using different spatial streams of data. Its extension on the access point side is called MU-MIMO or Multi-User MIMO. As the name suggests, it provides an access point such that multiple users can be connected via MIMO at once. MU-MIMO in Wi-Fi 6 allows multiple users to communicate with multiple antennas on the router simultaneously. In particular, Wi-Fi 6 allows multiple simultaneous beams (up to 8) to be supported by one access point, connecting to multiple devices simultaneously for downlink and uplink. 5G systems also encompass multi-user MIMO (up to 4 simultaneous indoor and 16 outdoor multiple beams) as well as distributed base stations, whether in the form of cloud RAN or Cooperative Multipoint (CoMP) systems.

Beamforming is a technique that concentrates a wireless signal towards a specific receiving device rather than broadcasting the signal in all directions like in a broadcast antenna. Due to the nature of electromagnetic waves, signals from a single antenna radiate in all directions unless blocked by a physical object. So, in order to focus the signal in a specific direction and form a targeted beam of electromagnetic energy, several nearby antennas broadcast the same signal at slightly different times. This beamforming process focuses a signal in a specific direction. In 5G beamforming, a large number of antennas in a 5G base station direct beams to user devices both horizontally and vertically to improve throughput and efficiency. Likewise, Beamforming is basic to the Wi-Fi 6 standard and supports eight antennas. Additionally, MU-MIMO uses Beamforming to ensure that router communication is effectively targeted to each connected user.

The central idea of ​​spatial multiplexing is to create multiple sub-channels so that multiple data streams can be simultaneously transmitted and retrieved through the channel. For this, the data stream is pre-coded before transmission and then combined after reception. This requires multiple transmitters and receivers. In Wi-Fi 6, an access point can send multiple single streams of data (or separate segments of a message) between the transmitter and the receiver. The number of transmitted and received streams corresponds to the number of unique data streams possible in a given access point, at most 8 in the case of Wi-Fi 6. Equivalently, in 5G spatial multiplexing, the data streams traverse multiple transmitters and receivers between base station and user equipment with maximum support for 4 indoor data streams and 16 outdoor data streams.

Cross-domain SEP and commercialization potential

Therefore, the common technologies of 5G and Wi-Fi 6, as discussed above, pave the way for corresponding SEPs to belong to both domains and be considered cross-domain SEPs. Such SEPs can maximize commercialization potential because they can be made non-exclusive in multiple patent pools, thereby generating more revenue and improving availability. In addition, it will be beneficial to identify more such domains and their respective cross-domain SEPs so that the SEPs can be used to their maximum advantage. Ultimately, cross-domain SEPs represent a major step forward in commercializing SEPs in the future.

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Author: thomaseder