Why is 4G not enough?
LTE, designed primarily to serve smart phones and improve users’ wireless internet experience, has been a great success. First deployed 6 years ago, 4G LTE has become the fastest-growing mobile technology in history. Today it globally supports approximately 500 million subscribers.
Since its launch, LTE has evolved to support higher peak bit rates and improve interworking with other radio access technologies such as WLAN. It will continue to evolve for the next ten years or so with expected key features to include:
• LTE radio interface improvements, such as 3D Multiple Input Multiple Output (MIMO) and wider Carrier Aggregation (CA)
• Deployment of LTE carriers in unlicensed and shared spectrum
• Heterogeneous Network (HetNet) improvement with Dual Connectivity (DC) and Coordinated MultiPoint (CoMP)
• Enhanced interworking solutions for Multiple Radio Access Technologies (Multi-RAT), especially between LTE and WLAN
• Improved coverage with in-band support for machine-type devices
At the same time, networks and networking topologies are anticipated to evolve with the introduction of new platform technologies such as:
• Network Function Virtualization (NFV) and Software De”ned Network (SDN)
• New forms of interworking based on multi-connectivity solutions such as IP binding and Multipath Transmission Control Protocol (MPTCP)
• Virtualized RAN (vRAN), a concept developed by Alcatel-Lucent introducing a new “local node” hosting centralized baseband processing and RAN optimization features With all these new features, why can’t we simply evolve LTE? The answer is simple. The set of requirements for 5G is not economically or technically achievable with the evolution of 4G. Some of the main challenges include:
• Advanced mission critical services and immersive virtual reality will eventually require extremely low end-to-end service latency of less than 1 millisecond. This will challenge the basis of the LTE framework and the hybrid retransmission approach used to handle error correction which effectively limits latency to approximately 10 milliseconds.
• With wide spread adoption of IoT devices, the RAN will need to handle extreme device connection density, up to 200,000 devices per km². Because LTE is connection-oriented, the signaling overhead will become a major issue as soon as the device density increases. What is required is a connectionless service.
• Desire by mobile operators to offer a more consistent Quality of Experience (QoE) rather than simply promoting raw peak bit rates will push the RAN to support a more #exible optimization for a more uniform delivered bit rate.
• The need to optimize the radio interface to simultaneously meet a wider range of use cases will drive the need for a more adaptable radio and core network solution than LTE/EPC.
• Ongoing traf”c growth in high density zones will eventually exceed what can be supported in the spectrum bands in which LTE was designed to operate, leading to a need for new radio access technologies optimized for new spectrum bands above 20 GHz.
• Need to evolve the security infrastructure to handle a signi”cantly large number of attached devices will encourage the adoption of more distributed solutions based on chain of trust using veri”able credentials These new requirements for the mobile network suggest that a new 5G radio interface is necessary and able to operate in frequency bands similar to existing cellular networks to provide wide area coverage for all devices and device types. Furthermore, to provide massive broadband capacity, it will be necessary to complement this new 5G radio interface with existing LTE and WLAN carriers on both the macro and small cell layers as well as with new higher frequency (e.g. millimeter Wave or mmWave) 5G carriers on small cells to augment capacity in high density urban areas.
Source from ALU.
