| 1. |
- Muneer, Sidra, et al.
(författare)
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Handling PA Nonlinearity in Massive MIMO : What are the Tradeoffs between System Capacity and Power Consumption
- 2020
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Ingår i: Conference Record of the 54th Asilomar Conference on Signals, Systems and Computers, ACSSC 2020. - 1058-6393. - 9780738131269 ; 2020-November, s. 974-978
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Konferensbidrag (refereegranskat)abstract
- Massive MIMO enables a very high spectral efficiency by spatial multiplexing and opens opportunities to reduce transmit power per antenna. On the other side, it also introduces new challenges in tackling the power amplifier nonlinearity due to the increased number of antennas. The behavior of Out-of-Band radiation from PAs in Massive MIMO is non-trivial depending upon the applied precoding scheme, propagation environment, and how the users are distributed spatially. In this paper, we analyze the in-band and Out-of-Band power distribution in space for a Massive MIMO base station with nonlinear power amplifiers. We also study the tradeoff between amplifier power consumption and system performance (in terms of error vector magnitude at intended receivers) for PAs with different backoff operating levels. The spatial analysis of Out-of-Band under more realistic channel conditions is more reflective of the situation, to determine system emission requirements. The tradeoff between performance and power consumption will provide a basis for future investigations into the design of efficient Massive MIMO systems, taking nonlinearities into account.
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| 2. |
- Muneer, Sidra, 1988-, et al.
(författare)
-
Single Frequency Network based Distributed Cooperative Routing : with CSMA MAC
- 2015
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Ingår i: Proceedings - 2015 13th International Conference on Frontiers of Information Technology, FIT 2015. - Islamabad. ; , s. 246-251
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Konferensbidrag (refereegranskat)abstract
- The multi-hop ad-hoc networking paradigm isexpected to be a key feature in future wireless communicationsystems. In a typical data broadcast scenario, multi-hop ad-hocrouting protocols allow devices (called nodes in this paper) tocommunicate and form networks in a manner to enable them tosuccessfully communicate and share information with all othernodes. To ensure maximum reachability in a multi-hop network,the concept of cooperative diversity, in which multiple nodescooperate to transmit the same data to a destination, can beapplied. The cooperative diversity is best exploited with the use ofSingle Frequency Networks (SFNs), also known as a form ofMacro-diversity. This work comprises of a design and analysis ofan SFN based distributed cooperative routing protocol (SFNDCRP)for multi-hop ad-hoc networks with a focus on routinginitiation phase with CSMA as a synchronization mechanism. Theproposed protocol is proactive and incurs minimum per packetdelay. The total delay in routing initiation phase for a network ofn nodes is identified as a problem of n2+2n. A delivery rate orreachability improvement of up-to 36% points for a node isobserved for the SFN based protocol as compared to a non-SFNbased protocol. For synchronization, a CSMA MAC protocol isdeployed for which a deficiency of only less than 0.1 percent existsin the measurements due to collisions in the network.
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| 3. |
- Muneer, Sidra, et al.
(författare)
-
System Design and Performance for Antenna Reservation in Massive MIMO
- 2022
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Ingår i: 2022 IEEE 96th Vehicular Technology Conference, VTC 2022-Fall 2022 - Proceedings. - 1550-2252. - 9781665454681 ; 2022-September
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Konferensbidrag (refereegranskat)abstract
- Peak to average power (PAPR) reduction of OFDM signals is critical in order to improve power amplifier (PA) efficiency in base stations. For massive MIMO, the complexity of these methods can become a real bottleneck in implementing low power digital signal processing chains. In this work, we consider an antenna reservation technique, which uses a low complexity clipping method to reduce signal peaks and leverages the benefit of massive antennas, by reserving a subset of antennas in order to compensate for the clipping distortion. Reserving antennas on the other hand reduces the potential array gain in the massive MIMO system, complicating the application of antenna reservation. This work explores various design space parameters in antenna reservation such as number of reserved antennas, amount of peak reduction and clipping methods. We investigate the impact of these parameters on the error vector magnitude at the user and on the adjacent channel power ratio at both transmitter and user positions. Our results enable a deeper understanding of antenna reservation as a low complexity PAPR reduction method in massive MIMO systems.
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