An thrilling new function has emerged within the third launch of the third technology partnership venture (3GPP) 5G commonplace–Launch 17. RedCap, brief for decreased functionality, will allow many use circumstances that solely require medium throughput and latency (assume IoT).  Whereas many IoT purposes have decrease capability and latency necessities, they’ve extra stringent value and energy consumption constraints not effectively addressed by the earlier 5G commonplace releases. RedCap is right here to fill the hole.
So, what’s RedCap?
To reply this query, we have to return in time as a result of the arrival of RedCap outcomes from the evolution of 5G. The 5G specification first emerged in 3GPP Launch 15 and has advanced tremendously. The primary launch targeted on assembly the calls for of the improved cell broadband (eMBB) use case for high-speed information charges and capability, specifying a brand new air interface to allow higher information throughput and laying the groundwork for low latency and better reliability purposes.
Launch 16 raised the bar on latency and bandwidth. Along with bringing enhancements over Launch 15 for capability and operational effectivity, this launch expanded 5G’s attain into new verticals, together with the commercial web of issues (IIoT).
Nonetheless, one thing was lacking. Many IoT use circumstances don’t have excessive throughput and tight latency necessities, but time, value, and energy consumption are vital issues for these purposes. The newest 5G launch from the 3GPP (Launch 17) addresses the wants of those use circumstances with RedCap.
RedCap introduces assist for wi-fi gadgets with decreased capabilities within the 5G specification. These gadgets are much less advanced, decrease value, and eat much less energy than their 5G counterparts. The 3GPP technical report (TR) 38.875 specifies three use circumstances for RedCap gadgets, together with industrial sensors, surveillance gadgets (essential for good cities and factories), and well being wearables. The 3GPP TR specifies the utmost information fee, end-to-end (E2E) latency, and repair availability for every use case, as proven in Desk 1, and different necessities.
Desk 1 RedCap use circumstances in 3GPP TR 38.875.
How does RedCap work?
RedCap implements a number of methods to cut back the complexity, value, and energy consumption of 5G gadgets. One of many foremost cost-reduction methods is to make use of fewer antennas within the machine, which additionally reduces the utmost variety of multiple-input multiple-output (MIMO) layers. RedCap gadgets solely assist 2×2 MIMO for the downlink and single-input single-output (SISO) for the uplink. Â
RedCap gadgets additionally assist decrease bandwidths than different 5G terminals. These gadgets solely assist bandwidths of 20 MHz for frequency vary 1 (FR1) and 100 MHz for frequency vary 2 (FR2). Decrease bandwidths scale back energy amplifier (PA) prices.
As well as, RedCap can use half-duplex frequency division duplex (HD-FDD) transmission as an alternative of full-duplex FDD (FD-FDD), which prevents the machine from transmitting and receiving information on totally different frequencies on the identical time. Half-duplex FDD operation helps scale back prices by eliminating the necessity for isolating the transmit path from the obtain path in a tool that helps simultaneous two-way communications. RedCap gadgets can thus use switches as an alternative of duplexers.
Whereas RedCap cost-reduction methods additionally generate vitality financial savings, these gadgets make use of different means to cut back energy consumption extra successfully. To begin, RedCap reduces the variety of blind decoding (BD) and management channel factor (CCE) limits monitored by the machine within the bodily downlink management channel (PDCCH), saving the vitality the machine makes use of to carry out these duties.
RedCap additionally makes use of the system body quantity (SFN) method to extend prolonged discontinuous reception (eDRX) cycles when the machine disconnects from the community or turns into idle, growing the machine’s battery life considerably. Longer eDRX cycles are useful in particular use circumstances resembling industrial sensors. Launch 17 additionally permits RedCap gadgets to transmit information with out connecting to the community.
As well as, RedCap loosens the radio useful resource administration (RRM) necessities. Stationary RedCap gadgets (and different RedCap gadgets doubtlessly) can profit from the relaxations to avoid wasting vitality and improve battery life. Â
What’s RedCap’s impression on machine and community operation?
RedCap modifications to cut back machine complexity, value, and energy consumption have implications for each gadgets and the community. Decrease bandwidths require adjustments in bandwidth half (BWP) configurations for the downlink and the uplink. New data parts (IE) allow the bandwidth to adapt dynamically primarily based on the actions taken by the machine.
Low bandwidths additionally impression the random-access channel (RACH) process utilized by the gadgets to entry the community. The community can specify a BWP for RedCap gadgets or scale back the scale of the BWP for these gadgets to connect to the community.
Utilizing half-duplex operation additionally creates points as a result of the gadgets can not transmit and obtain data concurrently. RedCap gadgets don’t detect scheduling data for the downlink and uplink in the identical set of symbols. These gadgets also can not monitor downlink messages whereas in uplink mode and ship uplink management data whereas monitoring the downlink.
The brand new signaling parameters and procedures launched in Launch 17 to allow the community to assist RedCap gadgets require machine engineers to verify the compatibility of their gadgets to make sure connectivity. 5G machine growth engineers additionally want instruments to verify RedCap parameters for debugging functions.
RedCap, filling the hole for IoT in 5G requirements
RedCap is the brand new child on the 5G block. Included within the newest launch of the 5G specification, this thrilling function opens doorways to a brand new array of use circumstances, significantly IoT purposes utilizing industrial sensors, surveillance gadgets, and well being wearables. By reducing the complexity, value, and energy consumption for 5G gadgets, RedCap additionally has an impression on machine and community operation. Testing is required to make sure machine connectivity earlier than launching RedCap gadgets commercially.
Jessy Cavazos is a part of Keysight’s Trade Options Advertising and marketing workforce.
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