Method and apparatus for hybrid RIS-based network to enhance network performance

Abstract

In the present invention, a hybrid network that includes both the passive and active RIS distribution based on the signal path traversal. The input required is the location of the BS and the UE to which the signal needs to be sent. If the UE is located withing a given boundary region of the BS, the RIS elements within the region can be turned off or considered to be operated in 'passive' mode as within the boundary the UE can tolerate the signal strength drop. However, if the UE is beyond the given boundary region, that is, the path loss occurring is significantly high then the RIS elements in the path of the signal traversal can be turned on or can be operated in the 'active' mode. This approach of selectively switching on and off of the RIS elements can significantly optimize the power consumption and also enhance the signal strength and thus network connectivity.

Description

Method and Apparatus for Hybrid RIS-based Network to Enhance Network PerformanceDESCRIPTION

[0001] With the advent of the reconfigurable intelligent surfaces, a lot of research is being carried on understanding the dynamics and functionalities of the RIS in enhancing the network connectivity. There are two types of RIS, active RIS and passive RIS. Passive RIS are responsible for reflecting the incident signal by adjusting the phase of the incidence and reflection. Since, they are passive elements they do not require an additional power input. However, signal suffers attenuation and pathloss in such a scenario. In case of active RIS, both the amplitude and the phase of the signal is significantly enhanced and modified to cater to the path loss occurring. Hence, active RIS needs an additional power supply source for operation. Since, the power supply is limited, there is always a tradeoff existing between the external power supply and signal gain.BRIEF DESCRIPTION OF DRAWINGS

[0002] Fig 1 illustrates hybrid network that includes both the passive and active RIS distribution based on the signal path traversal.

[0003] Fig 2 illustrates learning based Amplitude and Phase Control in RIS based Networks.

[0004] Fig.3 illustrates method and Apparatus for UAV assisted Strategic Cell Planning for Enhanced Coverage.

[0005] Fig.4 illustrates SWIPT Analysis based power optimization and signal radiation in RIS.DETAILED DESCRIPTION

[0006] We propose to come up with a hybrid network that includes both the passive and active RIS distribution based on the signal path traversal.

[0007] The FIG.l illustrates hybrid network that includes both the passive and active RIS distribution based on the signal path traversal. The input required is the location of the BS and the UE to which the signal needs to be sent. If the UE is located withing a given boundary region of the BS, the RIS elements within the region can be turned off or considered to be operated in 'passive' mode as within the boundary the UE can tolerate the signal strength drop. However, if the UE is beyond the given boundary region, that is, the path loss occurring is significantly high then the RIS elements in the path of the signal traversal can be turned on or can be operated in the 'active' mode. This approach ofselectively switching on and off of the RIS elements can significantly optimize the power consumption and also enhance the signal strength and thus network connectivity.

[0008] In one embodiment, RIS are surfaces which comprises of signal reflecting elements. There are two types of RIS, active RIS and passive RIS. Passive RIS are responsible for reflecting the incident signal by adjusting the phase of the incidence and reflection. Since, they are passive elements they do not require an additional power input. However, signal suffers attenuation and pathloss in such a scenario. In case of active RIS, both the amplitude and the phase of the signal is significantly enhanced and modified to cater to the path loss occurring. Hence, active RIS needs an additional power supply source for operation. The amplitude and phase control of the active and passive elements will play a significant role in the network performance.

[0009] FIG.2 illustrates Learning based Amplitude and Phase Control in RIS based Networks. The Learning based algorithms that can dynamically learn the location of the BS and UE, the channel through which the signal propagates and path loss components associated can help to control the phase and amplitude shifts required for reflecting the signal. There can be an initial training phase where the BS synchronizes with the UE with the help of the RIS elements. Training phase shall consist of few trials of downlink transmission to the UE until the appropriate phase and amplitude shifts are determined and the throughput is maximized. This phase and amplitude modifications and the signal path can be learnt for further uplink and downlink transmissions. This proposed learning approach can be beneficial in the enhancing the signal strength and the overall throughput gain of the network.

[0010] In one embodiment, UAVs can be deployed as mobile BS to extend the network coverage to areas that are not easily accessible by the BS. In this abstract, we propose RIS mounted UAVs that can be deployed in a given region to extend the cellular coverage thereby increasing the user connectivity and reaching out to areas that are not easily accessible by the BS, for instance, during calamities. The FIG.3 illustrates Method and Apparatus for UAV assisted Strategic Cell Planning for Enhanced Coverage. Using RIS mounted on the UAVs shall help establish connectivity between the main BS and the UEs via a hop-network mechanism. These RIS mounted UAVs can adjust and dynamically fix their locations based on the user's location and to where the connectivity needs to be ensured. This shall enhance flexibility to the cellular coverage region.

[0011] In another embodiment, an approach to introduce some intelligent features into the RIS that can help optimize the power consumption and also enhance the coverage. We assume that the RIS in a given network can choose to function in either the active state orpassive state. Active RIS elements require additional power supply to tune the amplitude and phase of the signal whereas passive RIS elements do not require any external power supply and they only reflect the incident signal. In a network architecture, operating all the RIS elements in active state would consume significant power and energy whereas allocating all the elements for passive mode of functioning would reduce the reflected signal strength thereby reducing the coverage capacity. Hence, we need to come up with an approach that can provide information related to the active and passive state functioning of the RIS which shall help in optimized usage of the power supply available along with enhancing the coverage of a network.

[0012] Fig.4 illustrates SWIPT Analysis based power optimization and signal radiation in RIS. According to the Free Space equation, the received power at any location d from the transmitter is inversely proportional to the square of the distance. According to simultaneous wireless information and power transfer (SWIPT) analysis, a signal incident at any location can be utilized to convey both energy and information. However, there is a tradeoff between the information conveyed and the energy that can be transferred. We suggest to implement the SWIPT methodologies for the RIS that shall help in both power supply to the device for active mode operation and can also convey control information through the incident signals. This control information can be decoded to decide if the RIS shall operate in the active or passive mode. This way we can turn off the RIS elements which are not involved in a given signal transmission and optimize the resource allocation and coverage extension.

[0013] In another embodiment, The Direct Sequence Spread Spectrum (DSSS) employs a code which is pseudo random in nature. This chipping code has a higher bandwidth compared to the payload data. Each data bit is spread over a higher bandwidth using this chipping code. The receiver first needs generate the same code and synchronize itself transmitted code and doppler if any. Once this alignment happens the decoding the data bits can start. Overall, due to the spreading, DSSS has a low bandwidth efficiency. Even so, it is the most preferred waveform in communication links needing higher security, anti-jamming, and low probability of interception (LPI). The proposed scheme encodes N consecutive data bits, which is transmitted in a single bit duration of the standard approach, thereby increasing the throughput N times. The paper discusses the encoding and decoding technique in detail from the transmitter and receiver perspective. Simulation results, implementation aspects are also covered. « FIG. 0»

Claims

CLAIMSI / Wc Claim,1. Method, system and apparatus providing one or more features as described in the paragraphs of this specification.

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