Flexible Dual-Connectivity Spectrum Aggregation for Decoupled Uplink and Downlink Access in 5G Heterogeneous Systems

Abstract

Maintaining multiple wireless connections is a promising solution to boost capacity in fifth-generation (5G) networks, where user equipment is able to consume radio resources of several serving cells simultaneously and potentially aggregate bandwidth across all of them. The emerging dual connectivity paradigm can be regarded as an attractive access mechanism in dense heterogeneous 5G networks, where bandwidth sharing and cooperative techniques are evolving to meet the increased capacity requirements. Dual connectivity in the uplink remained highly controversial, since the user device has a limited power budget to share between two different access points, especially when located close to the cell edge. On the other hand, in an attempt to enhance the uplink communications performance, the concept of uplink and downlink decoupling has recently been introduced. Leveraging these latest developments, our work significantly advances prior art by proposing and investigating the concept of flexible cell association in dual connectivity scenarios, where users are able to aggregate resources from more than one serving cell. In this setup, the preferred association policies for the uplink may differ from those for the downlink, thereby allowing for a truly decoupled access. With the use of stochastic geometry, the dual connectivity association regions for decoupled access are derived and the resultant performance is evaluated in terms of capacity gains over the conventional downlink received power access policies.

Business Case and Technology Analysis for 5G Low Latency Applications

“…Finally, 5G needs to be a fully converged network where different access types can be intelligently selected. Multiconnectivity has been a well-researched topic in later 4G releases (Release 13 and 14 [35]) and has shown good performance results when flexible network associations are allowed [36]. Hybrid access with the use of fixed and mobile networks can also enhance latency over the network, by reducing the impact of the LTE-A access delay.…”

Uplink Performance Enhancement Through Adaptive Multi-Association and Decoupling in UHF-mmWave Hybrid Networks

“…In the Min-PL criterion, the UEs are connected to the BS with the lowest path-loss [3,19]. A typical UE is associated with BS l in the UL if and only if…”

“…The association scheme in this part is different from the dual connectivity association scheme in [19] in the sense that UEs can connect to one more BS if higher capacity can be achieved. Only a small portion of the UEs may be connected to two BSs, and thus UEs can connect in a single or dual hybrid connectivity.…”

“…However, as the transmit power of UEs is limited, adopting this in the UL could be counterproductive unless combined with DUDe to make it more power efficient. The technical challenges imposed by this approach and the potential solutions are discussed in [18,19]. 1 UHF refers to the radio frequencies in the range between 300 MHz and 3GHz.…”

Upload User Collaboration in the Data Upload for LTE-Advanced Networks

“…In [62], the authors mention that a proper solution to increase capacity in the future mobile network is maintaining multiple wireless connections. This means that a UE is capable to use multiple radio resources of different serving eNBs simultaneously, and potentially employ carrier aggregation over all those resources.…”