arXiv subjects

Joshua Roy Palathinkal

Publications and source records attributed to Joshua Roy Palathinkal.

8 recordsLinked to original sources

arXiv2026

App-Based Performance Characterization of Cellular and Wi-Fi Networks in Dense Stadium Deployments

The concentration of 77,622 spectators during football games at Notre Dame Stadium creates an exceptionally demanding environment for wireless infrastructure. To handle this extreme user density, the stadium deploys concurrent multi-tier networks serving outdoor users: an enterprise 5/6 GHz Wi-Fi network with ~900 outdoor Access Points (APs) alongside high-density multi-carrier 4G/5G networks powered by a neutral-host small-cell Distributed Antenna System (DAS) with up to 129 unique cell identifiers (PCIs) per operator. This study evaluates user-perceived performance and QoE across these networks using commercial smartphones to execute web browsing, WhatsApp messaging, and Instagram media posting workloads. Our empirical results reveal that while cellular networks deliver strong peak downlink performance in an empty stadium, game-day crowd loads heavily strain uplink and latency performance, triggering a severe cellular "uplink gap." Under Non-Standalone (EN-DC) anchor congestion, web browsing handshakes suffer a catastrophic 5,983 ms P90 Time-to-First-Byte (TTFB), and image upload failure rates climb to 46%. Furthermore, while narrow low-band FDD channels (e.g., n5) maintain robust channel quality during uploads, they exhibit a 70% median Block Error Rate (BLER) during active browsing tests, driving a 36.6% page-load failure rate. Conversely, the dense stadium Wi-Fi infrastructure delivers downlink throughput comparable to the best performing 5G Standalone (SA) deployment while providing better uplink and latency resilience, yielding the lowest game-day page-load failure rate (3.9%) and bounding image upload latency degradation to just 2.1x relative to empty-stadium baselines. These insights proves that densification through localized Wi-Fi deployment is essential to absorb severe stadium traffic spikes.

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arXiv2026

Comprehensive Analysis of Cellular Uplink Performance in a Dense Stadium Deployment

Uplink performance remains a critical limitation in modern 5G networks, where UEs have to balance limited transmission power against propagation challenges. We conducted extensive measurements in the University of Notre Dame's football stadium, which has a seating capacity of 80,000 spectators, evaluating network behavior under both unloaded (pregame) and severely congested (game day) conditions, with a focus on uplink performance. Analyzing PHY-layer metrics captured via the Rohde & Schwarz QualiPoc, we show that high-frequency TDD bands in the uplink are severely bottlenecked in both the spectral and temporal domains. Despite transmitting near maximum 3GPP power limits, propagation loss inherent to high-frequency bands restricts UEs to low MCS indices and low PRB allocations, even in unloaded networks. This inability to achieve wideband allocation is further compounded by the significantly smaller number of uplink slots compared to downlink slots in TDD frames. Consequently, we observe a severe disparity between uplink and downlink: while high-frequency TDD bands carry the majority of downlink throughput, the network relies heavily on lower-frequency FDD bands for uplink. Additional measurements under favorable propagation conditions around a Verizon COW deployment located in the stadium parking lot also show that this limitation is not solely propagation-driven; rather, the duplexing scheme itself also plays a significant role. Even when TDD bands achieve higher or comparable MCS, FDD bands have a performance edge in the uplink due to the restrictive, downlink-heavy TDD architecture. These findings emphasize the indispensable role of low-frequency FDD spectrum in sustaining uplink capacity, providing insights that will help guide the design of next-generation wireless networks.

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arXiv2026

Evaluation of the effects of 3GPP-specific beamforming and channel estimation on the 3D EIRP profile of a 5G gNB

Spatial domain exploitation through 3D beamforming serves as a critical technology enabler for performance enhancement in the Fifth Generation New Radio (5G NR) specification. This is realized at the gNodeB (gNB) through the integration of massive antenna element arrays that facilitates 3D spatial multiplexing. However, these systems with high-directional transmissions also represent a threat to incumbent services such as radar and satellites. These incumbents already operate in midband spectrum\textemdash{}including the 4.4-4.9 GHz and 7.125-7.4 GHz bands\textemdash{}that are currently being evaluated for future cellular deployments. Here, we present the first work that evaluates the transmitted Effective Isotropic Radiated Power (EIRP) of a gNB in 3D space, using the 3GPP Release-18 standard for FR-1 instead of theoretical analyses of beam nulling, which can be simplistic. We shed light on the problems requiring attention with the EIRP profile in 3D space for existing codebook designs predefined in 3GPP: i) interference from a gNB does not depend only on the worst-case beamforming direction, but on a variety of beamforming directions due to side-lobes; ii) advanced antenna systems (AAS) architecture and antenna port configurations play a crucial role in average 3D EIRP, which are implementation dependent, and iii) we introduce two beam nulling methods, which achieve a 11 dB power reduction toward a target direction, with 3.5-4.5 dB SNR loss in UE link performance at a 10^{-4} bit error rate (BER) across modulation schemes under ideal and practical channel estimation, a higher loss compared to predictions from theoretical analyses.

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arXiv2026

Evaluating Smartphone GNSS Accuracy for Geofenced 6 GHz Operations

The recently deployed 6 GHz spectrum in the U.S. utilizes distinct power categories, with the latest proposed "Geofenced Variable Power" (GVP) category permitting indoor and outdoor operations without continuous Automated Frequency Coordination (AFC) by relying instead on local databases of exclusion zones. Consequently, the safe operation of GVP devices depends entirely on reliable GNSS localization to respect these geofences. However, GNSS accuracy is highly variable and significantly degrades in environments like urban canyons or indoors. This paper presents the first comprehensive empirical study evaluating GNSS reliability specifically for GVP compliance. Utilizing the SigCap Android application, we document and compare GNSS accuracy across an extensive array of real-world conditions, encompassing urban versus suburban landscapes, varying mobility states (stationary, walking, driving), and indoor versus outdoor settings. The results demonstrate that while device hardware causes variations in GNSS accuracy, the operational environment is the primary driver of error. Indoor settings and dense urban areas consistently degrade localization. Moreover, outdoor positions adjacent to buildings often surprisingly produce significant inaccuracies, even near low-elevation structures. We further analyze the contribution of different GNSS constellations to device positioning and show that satellites from non-U.S.-licensed constellations-although currently used in a substantial portion of location fixes-are not permitted for regulatory geolocation under FCC requirements.

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arXiv2026

Indoor Neutral-Host Networks Over Shared Spectrum and Shared Infrastructure: A Comparison Study of Real-World Deployments

Indoor high-capacity connectivity is frequently constrained by significant building penetration loss and the inherent uplink power limitations of a typical outdoor macro-cell deployment. While Mobile Network Operators (MNOs) must optimize spectrum across low-band (<1 GHz) and mid-band (1-7 GHz) frequencies, uplink performance remains disproportionately degraded due to link budget asymmetry. Neutral-host (NH) networking provides a scalable alternative by transparently offloading MNO subscribers via spectrum sharing and shared infrastructure. We present a multi-site measurement study comparing Citizens Broadband Radio Service (CBRS)-enabled NH networks against public MNO 4G/5G macro deployments and Wi-Fi. Our results show: (i) significant building penetration loss with up to 15.5 dB in low-bands and 17.9 dB in mid-bands, resulting in a ~10 dB RSRP deficit for MNO mid-bands compared to low-bands; (ii) NH networks provide a 30 dB higher median indoor RSRP with indoor NH normalized downlink throughput matches MNO outdoor performance, while its uplink performance exceeds MNO levels in both indoor and outdoor settings; (iii) NH proximity enables superior uplink efficiency, utilizing 64-QAM for 56% of transmissions (versus <6% for MNOs) and reducing median UE transmit power by 5 dB; (iv) MNOs rely on low-band spectrum for indoor uplink transmissions, while the NH deployment maintains high-performance mid-band connectivity; and (v) NH outperforms MNOs in end-to-end throughput but trails Wi-Fi in uplink throughput and latency due to packet routing overhead to the MNO core.

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arXiv2025

Indoor Sharing in the Mid-Band: A Performance Study of Neutral-Host, Cellular Macro, and Wi-Fi

Indoor environments present a significant challenge for wireless connectivity, as immense data demand strains traditional solutions. Public Mobile Network Operators (MNOs), utilizing outdoor macro base stations (BSs), suffer from poor signal penetration. Indoor Wi-Fi networks, on the other hand, may face reliability issues due to spectrum contention. Shared spectrum models, particularly the Citizens Broadband Radio Service (CBRS) utilized by private 4G/5G networks, have emerged as a promising alternative to provide reliable indoor service. Moreover, these private networks are equipped with the neutral-host (NH) model, seamlessly offloading indoor MNOs' traffic to the private CBRS network. This paper presents a comprehensive, in-situ performance evaluation of three co-located technologies utilizing mid-bands spectrum (1-6 GHz)--a CBRS-based NH network, public MNO macro networks, and a Wi-Fi 6 network--within a large, big-box retail store characterized by significant building loss. Our analysis demonstrates: (i) the NH network provides superior indoor coverage compared to MNO macro, requiring only six CBRS devices (CBSDs)--versus 65 Access Points (APs) for enterprise Wi-Fi--to achieve full coverage, with a median building loss of 26.6 dB ensuring interference-free coexistence with outdoor federal incumbents; (ii) the NH network achieves substantial indoor throughput gains, with per-channel normalized throughput improvements of 1.44x and 1.62x in downlink (DL), and 4.33x and 13x in uplink (UL), compared to 4G and 5G macro deployments, respectively; (iii) the NH deployment achieves a median indoor aggregated physical (PHY)-layer DL throughput gain of 2.08x over 5G macro deployments indoors, despite utilizing only 40 MHz of aggregated bandwidth compared to 225 MHz for 5G macro; and (iv) the NH deployment also outperforms Wi-Fi in application-layer HTTP DL performance by 5.05x.

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arXiv2025

Evaluation of Indoor/Outdoor Sharing in the Unlicensed 6 GHz Band

Standard Power (SP) Wi-Fi 6E in the U.S. is just beginning to be deployed outdoors in the shared but unlicensed 6 GHz band under the control of an Automated Frequency Coordination (AFC) system to protect incumbents, while low-power-indoor (LPI) usage has been steadily increasing over the past 2 years. In this paper, we present the first comprehensive measurements and analyses of a SP Wi-Fi 6E deployment at the University of Notre Dame's football stadium, with 902 access points and a seating capacity of 80,000, coexisting with LPI deployments in adjacent buildings. Measurement campaigns were conducted during and after games, outdoors and indoors to fully characterize the performance of SP Wi-Fi 6E, interactions between SP and LPI and potential for interference to incumbents. Our main conclusions are: (i) in a very short time of about 2 months, the percentage of Wi-Fi 6E client connections is already 14% indicating rapid adoption, (ii) dense SP operation outdoors can negatively impact LPI deployments indoors, depending on building loss, indicating the need to carefully consider hybrid indoor-outdoor sharing deployments, and (iii) spectrum analyzer results indicate an aggregate signal level increase of approximately 10 dB in a Wi-Fi channel during peak usage which could potentially lead to interference since the AFC does not consider aggregate interference when allocating permitted power levels. These results from real-world deployments can inform spectrum policy in other bands where similar sharing mechanisms are being considered, such as 7.125 - 8.4 GHz.

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arXiv2025

Neutral-Hosts In The Shared Mid-Bands: Addressing Indoor Cellular Performance

The 3.55 - 3.7 GHz Citizens Broadband Radio Service (CBRS) band in the U.S., shared with incumbent Navy radars, is witnessing increasing deployments both indoors and outdoors using a shared, licensed model. Among the many use-cases of such private networks is the indoor neutral-host, where cellular customers of Mobile Network Operators (MNOs) can be seamlessly served indoors over CBRS with improved performance, since building loss reduces the indoor signal strength of mid-band 5G cellular signals considerably. In this paper, we present the first detailed measurements and analyses of a real-world deployment of an indoor private network serving as a neutral-host in the CBRS band serving two MNOs. Our findings demonstrate significant advantages: (i) minimal outdoor interference from the CBRS network due to over 22 dB median penetration loss, ensuring compatibility with incumbent users; (ii) substantial indoor performance gains with up to 535$\times$ and 33$\times$ median downlink and uplink throughput improvements, respectively, compared to the worst-performing MNO; (iii) reduced uplink transmit power for user devices (median 12 dB reduction), increasing energy efficiency; and (iv) significant capacity offload from the MNO network (median 233 resource blocks/slot freed in 5G), allowing MNOs to better serve outdoor users. These results highlight the potential of low-power indoor CBRS deployments to improve performance, increase spectrum efficiency, and support coexistence with current and future incumbents, e.g., the 3.1 - 3.45 GHz band being considered for sharing with federal incumbents in the U.S.

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