Obstacle avoidance cell discovery using mm-waves directive antennas in 5G networks

Abstract

Abstract-With the advent of next-generation mobile devices, wireless networks must be upgraded to fill the gap between huge user data demands and scarce channel capacity. Mm-waves technologies appear as the key-enabler for the future 5G networks design, exhibiting large bandwidth availability and high data rate. As counterpart, the small wave-length incurs in a harsh signal propagation that limits the transmission range. To overcome this limitation, array of antennas with a relatively high number of small elements are used to exploit beamforming techniques that greatly increase antenna directionality both at base station and user terminal. These very narrow beams are used during data transfer and tracking techniques dynamically adapt the direction according to terminal mobility. During cell discovery when initial synchronization must be acquired, however, directionality can delay the process since the best direction to point the beam is unknown. All space must be scanned using the tradeoff between beam width and transmission range.Some support to speed up the cell search process can come from the new architectures for 5G currently being investigated, where conventional wireless network and mm-waves technologies coexist. In these architecture a functional split between C-plane and U-plane allows to guarantee the continuous availability of a signaling channel through conventional wireless technologies with the opportunity to convey context information from users to network.In this paper, we investigate the use of position information provided by user terminals in order to improve the performance of the cell search process. We analyze mm-wave propagation environment and show how it is possible to take into account of position inaccuracy and reflected rays in presence of obstacles.

A Tutorial on Beam Management for 3GPP NR at mmWave Frequencies

“…[23], [24], [25] More advanced searching schemes. [26], [27], [28], [29] Context-aware initial access. [30], [31] Performance comparison.…”

“…Context information can also be exploited to improve the cell discovery procedure and minimize the delay [26], [27], while capturing the effects of position inaccuracy in the presence of obstacles. In the scheme proposed in [28], booster cells (operating at mmWave) are deployed under the coverage of an anchor cell (operating at LTE frequencies).…”

Inverse Multipath Fingerprinting for Millimeter Wave V2I Beam Alignment

“…This can eliminate the beam training overhead but it only works when the LOS path is available. More elaborate channel models with LOS obstruction have been investigated in [28], [29]. It is proposed in [28] to memorize successful beam configurations observed in the past but no detail is given on how to rank those configurations in terms of their likelihood to provide a good link.…”

“…More elaborate channel models with LOS obstruction have been investigated in [28], [29]. It is proposed in [28] to memorize successful beam configurations observed in the past but no detail is given on how to rank those configurations in terms of their likelihood to provide a good link. Omnidirectional antennas at the users are assumed in [28], which may be impractical for mmWave communications.…”

Millimeter Wave Communications for Future Mobile Networks

“…In order to reduce the delay due to exhaustive search procedures, the authors in [211], [217], [218] implemented a faster user discovery method which employs a two-stage hierarchical procedure, while the use of context information about user and/or BS positions, provided by a separate control plane, was considered in [214], [219]. In a refinement to the method in [219], the procedure to capture the effects of position inaccuracy and obstacles was implemented in [220]. In addition, the use of booster cells which operate at mm-Waves and under the coverage of a microwave-based anchor cell was proposed by the authors in [221].…”