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Proceedings ArticleDOI

Performance Evaluation of LTE and Wi-Fi Coexistence in Unlicensed Bands

TL;DR: A simulator-based system- level analysis in order to assess the network performance in an office scenario shows that LTE system performance is slightly affected by coexistence whereas Wi-Fi is significantly impacted by LTE transmissions.
Abstract: The deployment of modern mobile systems has faced severe challenges due to the current spectrum scarcity. The situation has been further worsened by the development of different wireless technologies and standards that can be used in the same frequency band. Furthermore, the usage of smaller cells (e.g. pico, femto and wireless LAN), coexistence among heterogeneous networks (including amongst different wireless technologies such as LTE and Wi-Fi deployed in the same frequency band) has been a big field of research in the academy and industry. In this paper, we provide a performance evaluation of coexistence between LTE and Wi-Fi systems and show some of the challenges faced by the different technologies. We focus on a simulator-based system- level analysis in order to assess the network performance in an office scenario. Simulation results show that LTE system performance is slightly affected by coexistence whereas Wi-Fi is significantly impacted by LTE transmissions. In coexistence, the Wi-Fi channel is most often blocked by LTE interference, making the Wi-Fi nodes to stay on the LISTEN mode more than 96% of the time. This reflects directly on the Wi-Fi user throughput, that decreases from 70% to ≈100% depending on the scenario. Finally, some of the main issues that limit the LTE/Wi-Fi coexistence and some pointers on the mutual interference management of both the systems are provided.
Citations
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Journal ArticleDOI
TL;DR: This is the first work that uses stochastic geometry to analyze the effect of channel access priorities of four traffic classes defined recently by 3GPP release 14, on the performance of the network and the degree of efficiency that can be achieved.

4 citations

Proceedings ArticleDOI
20 May 2019
TL;DR: The fair coexistence between LTE-U and Wi-Fi in the scenario where an LTE eNB can exchange information withWi-Fi access points (AP) is studied, which can be done in both wired and wireless mediums.
Abstract: One of the most prominent cellular technologies, Long Term Evolution (LTE), is currently operating on some 800MHz, 2GHz, and 3.5GHz licensed bands. Wi-Fi is currently operating on 2.5GHz and 5GHz unlicensed bands. The declaration stating that 5GHz bands are unlicensed enables LTE to operate on 5GHz bands. It is challenging, however, for different wireless technologies to co-exist. The two standards, LTE-U and LTE-LAA, for LTE to coexist with Wi-Fi on the 5GHz band have evolved. The LTE-U standard is based on the duty cycle, while LTE-LAA is based on listen-before-talk (LBT). In existing LTE-U systems, the LTE base station (eNB) estimates the fair portion of Wi-Fi usage based on channel state information. The usage estimation from channel state information is not as accurate enough as well as the fair portion. In this paper, we study the fair coexistence between LTE-U and Wi-Fi in the scenario where an LTE eNB can exchange information with Wi-Fi access points (AP). The communication can be done in both wired and wireless mediums. The wired medium is ethernet point-to-point communication, and the wireless communication is done using the reserved bits in Wi-Fi packets. Both ways are applicable to the operator, who has both LTE and Wi-Fi coverage. Therefore, the Wi-Fi AP can collect information about other APs and send it to its LTE eNB. The LTE eNB can adjust its parameters according to the received information to achieve fairness.

4 citations


Cites methods from "Performance Evaluation of LTE and W..."

  • ...The experiments conducted by Nokia Research [17] show that in coexistence scenarios, the Wi-Fi network is heavily influenced by LTE-U interference....

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Proceedings ArticleDOI
03 Dec 2015
TL;DR: A spatial adaptive play (SAP)-based L/U channel selection algorithm is proposed to achieve the optimal action profile for small cells with the consideration of operating bandwidth constraint and is proved to be an exact potential game.
Abstract: The rapidly growing mobile traffic urges the spectrum scarcity. An insightful and effective approach is to use additional spectrum to improve network capacity. In Rel-13, LTE deployment in unlicensed bands (LTE-U) is being considered. Technically, LTE-U can be deployed with the small cell. Then small cell can access both licensed and unlicensed spectrum. Unlicensed spectrum is free to use but will be shared by all small cells while licensed spectrum has to be paid. In this paper, we try to maximize sum utility of small cells with the consideration of operating bandwidth constraint. Each small cell has to decide which channels should be selected in licensed and unlicensed band. The local interaction game framework is introduced to solve the optimization problem. The game is proved to be an exact potential game and the optimal action profile for small cells constitutes a pure strategy NE. We then proposed a spatial adaptive play (SAP)-based L/U channel selection algorithm to achieve the optimal action profile. Simulation validates the efficiency of the algorithm.

4 citations


Cites background from "Performance Evaluation of LTE and W..."

  • ...Recently, researchers show their interest in the topic about LTE in unlicensed band....

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Journal ArticleDOI
TL;DR: An analytical model for the characterization of achievable throughputs of Wi-Fi and LTE-U networks in spatially distributed scenarios with downlink-prevalent traffic is presented and gives very high accuracy in throughput estimation and the mean normalized error is less than 3% for a 80-node scenario.

4 citations

Proceedings ArticleDOI
Jin Li1, Youngnam Han1
03 Apr 2016
TL;DR: Network capacity optimization problem for HetNet comprised of Long-Term Evolution small cell and wireless fidelity in LTE unlicensed spectrum (LTE-U) with optimal spectrum splitting ratio is considered and results reveal effectiveness of the proposed scheme.
Abstract: Efficient utilization of limited spectrum resource has been a major issue in wireless communication systems, which has triggered the design and development of advanced cellular networks. Recently, heterogeneous network (HetNet) with small cells to satisfy the demand for higher data rate transmission and throughput has attracted a lot of attention in the unlicensed spectrum bands environment to overcome the scarcity of licensed spectrum. In this paper, we consider network capacity optimization problem for HetNet comprised of Long-Term Evolution (LTE) small cell and wireless fidelity (Wi-Fi) in LTE unlicensed spectrum (LTE-U) with optimal spectrum splitting ratio. We derive coverage probabilities and average achievable rates for each radio access technologies (RATs) based on the conditions of user equipment (UE) association in multi-RAT wireless network system. Then the optimal unlicensed spectrum splitting ratio can be obtained by maximizing HetNet capacity under the derived constraints on respective coverage probabilities. Simulation results reveal effectiveness of the proposed scheme, where both the spectrum splitting ratio and transmit power ratio are key parameters. This analysis can be easily extended to HetNets with multiple RATs.

4 citations


Cites background from "Performance Evaluation of LTE and W..."

  • ...With the main challenge for LTE-U that LTE operation could take over the bands and force Wi-Fi to move to silent mode due to the carrier sense multiple access with collision avoidance (CSMA/CA) feature, elaborate design of LTE-U system is essential [6], [7]....

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References
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Journal ArticleDOI
TL;DR: An overview of the techniques being considered for LTE Release 10 (aka LTEAdvanced) is discussed, which includes bandwidth extension via carrier aggregation to support deployment bandwidths up to 100 MHz, downlink spatial multiplexing including single-cell multi-user multiple-input multiple-output transmission and coordinated multi point transmission, and heterogeneous networks with emphasis on Type 1 and Type 2 relays.
Abstract: LTE Release 8 is one of the primary broadband technologies based on OFDM, which is currently being commercialized. LTE Release 8, which is mainly deployed in a macro/microcell layout, provides improved system capacity and coverage, high peak data rates, low latency, reduced operating costs, multi-antenna support, flexible bandwidth operation and seamless integration with existing systems. LTE-Advanced (also known as LTE Release 10) significantly enhances the existing LTE Release 8 and supports much higher peak rates, higher throughput and coverage, and lower latencies, resulting in a better user experience. Additionally, LTE Release 10 will support heterogeneous deployments where low-power nodes comprising picocells, femtocells, relays, remote radio heads, and so on are placed in a macrocell layout. The LTE-Advanced features enable one to meet or exceed IMT-Advanced requirements. It may also be noted that LTE Release 9 provides some minor enhancement to LTE Release 8 with respect to the air interface, and includes features like dual-layer beamforming and time-difference- of-arrival-based location techniques. In this article an overview of the techniques being considered for LTE Release 10 (aka LTEAdvanced) is discussed. This includes bandwidth extension via carrier aggregation to support deployment bandwidths up to 100 MHz, downlink spatial multiplexing including single-cell multi-user multiple-input multiple-output transmission and coordinated multi point transmission, uplink spatial multiplexing including extension to four-layer MIMO, and heterogeneous networks with emphasis on Type 1 and Type 2 relays. Finally, the performance of LTEAdvanced using IMT-A scenarios is presented and compared against IMT-A targets for full buffer and bursty traffic model.

1,044 citations


"Performance Evaluation of LTE and W..." refers background in this paper

  • ...4GHz band has already been established [7], and the recent inclusion of features on LTE standard [12] are promoting its usage on pico and femto cells, it is possible that in the near future coexistence between LTE (-ADV) and Wi-Fi will become important....

    [...]

Journal ArticleDOI
TL;DR: Concepts underlying the "property" and "commons" debate are presented, options for spectrum reform are clarified, and the trade-offs of spectrum sharing are described.
Abstract: Many complain about severe spectrum shortage. The shortage comes from outdated spectrum policies that allows for little sharing. Regulators have granted licenses that offer exclusive access to the spectrum. When these licensees are not transmitting, the spectrum sits idle. A new technology regarding spectrum shortage enables more spectrum sharing that unleashes innovative products and services, provided that we adopt the appropriate spectrum policies. Two camps are pushing for extreme reform, one for "property rights" and the other for "spectrum commons". This article presents concepts underlying the "property" and "commons" debate, clarifies options for spectrum reform, and describes the trade-offs of spectrum sharing

592 citations


"Performance Evaluation of LTE and W..." refers background in this paper

  • ...One of the most promising techniques for dealing with the lack of available spectrum is the concept of spectrum sharing [1] ....

    [...]

Proceedings ArticleDOI
22 Apr 2007
TL;DR: An adjusted Shannon capacity formula is introduced, where it is shown that the bandwidth efficiency can be calculated based on system parameters, while the SNR efficiency is extracted from detailed link level studies.
Abstract: In this paper we propose a modification to Shannon capacity bound in order to facilitate accurate benchmarking of UTRAN long term evolution (LTE). The method is generally applicable to wireless communication systems, while we have used LTE air-interface technology as a case study. We introduce an adjusted Shannon capacity formula, where we take into account the system bandwidth efficiency and the SNR efficiency of LTE. Separating these issues, allows for simplified parameter extraction. We show that the bandwidth efficiency can be calculated based on system parameters, while the SNR efficiency is extracted from detailed link level studies including advanced features of MIMO and frequency domain packet scheduling (FDPS). We then use the adjusted Shannon capacity formula combined with G-factor distributions for macro and micro cell scenarios to predict LTE cell spectral efficiency (SE). Such LTE SE predictions are compared to LTE cell SE results generated by system level simulations. The results show an excellent match of less that 5-10% deviation.

580 citations


"Performance Evaluation of LTE and W..." refers methods in this paper

  • ...For physical layer (PHY) abstraction, Shannon-fitting [14] is employed to predict the PHY performance at the system-level....

    [...]

Proceedings ArticleDOI
09 Jun 2013
TL;DR: This paper considers two of the most prominent wireless technologies available today, namely Long Term Evolution (LTE), and WiFi, and addresses some problems that arise from their coexistence in the same band, and proposes a simple coexistence scheme that reuses the concept of almost blank subframes in LTE.
Abstract: The recent development of regulatory policies that permit the use of TV bands spectrum on a secondary basis has motivated discussion about coexistence of primary (e.g. TV broadcasts) and secondary users (e.g. WiFi users in TV spectrum). However, much less attention has been given to coexistence of different secondary wireless technologies in the TV white spaces. Lack of coordination between secondary networks may create severe interference situations, resulting in less efficient usage of the spectrum. In this paper, we consider two of the most prominent wireless technologies available today, namely Long Term Evolution (LTE), and WiFi, and address some problems that arise from their coexistence in the same band. We perform exhaustive system simulations and observe that WiFi is hampered much more significantly than LTE in coexistence scenarios. A simple coexistence scheme that reuses the concept of almost blank subframes in LTE is proposed, and it is observed that it can improve the WiFi throughput per user up to 50 times in the studied scenarios.

324 citations


"Performance Evaluation of LTE and W..." refers background in this paper

  • ...This kind of approach has started to be investigated in [16], where LTE/Wi-Fi coexistence is enabled by LTE blank subframe allocation....

    [...]

Proceedings ArticleDOI
27 Aug 2007
TL;DR: A channel hopping design is prototype using PRISM NICs, and it is found that it can sustain throughput at levels of RF interference well above that needed to disrupt unmodified links, and at a reasonable cost in terms of switching overheads.
Abstract: We study the impact on 802.11 networks of RF interference from devices such as Zigbee and cordless phones that increasingly crowd the 2.4GHz ISM band, and from devices such as wireless camera jammers and non-compliant 802.11 devices that seek to disrupt 802.11 operation. Our experiments show that commodity 802.11 equipment is surprisingly vulnerable to certain patterns of weak or narrow-band interference. This enables us to disrupt a link with an interfering signal whose power is 1000 times weaker than the victim's 802.11 signals, or to shut down a multiple AP, multiple channel managed network at a location with a single radio interferer. We identify several factors that lead to these vulnerabilities, ranging from MAC layer driver implementation strategies to PHY layer radio frequency implementation strategies. Our results further show that these factors are not overcome by simply changing 802.11 operational parameters (such as CCA threshold, rate and packet size) with the exception of frequency shifts. This leads us to explore rapid channel hopping as a strategy to withstand RF interference. We prototype a channel hopping design using PRISM NICs, and find that it can sustain throughput at levels of RF interference well above that needed to disrupt unmodified links, and at a reasonable cost in terms of switching overheads.

300 citations


"Performance Evaluation of LTE and W..." refers background in this paper

  • ...However, it is observed that the coexistence of heterogeneous systems in the same frequency bands causes a meaningful degradation on the system performance (e.g., Wi-Fi and Bluetooth [3], Wi-Fi and ZigBee [4], Wi-Fi and WiMAX [5])....

    [...]

  • ..., Wi-Fi and Bluetooth [3], Wi-Fi and ZigBee [4], Wi-Fi and WiMAX [5])....

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Trending Questions (1)
What is the difference between LTE Home Internet and FIOS?

Simulation results show that LTE system performance is slightly affected by coexistence whereas Wi-Fi is significantly impacted by LTE transmissions.