TL;DR: This paper studies the downlink capacity of edge users in a cellular network and sees whether base station cooperation improves the spectral efficiency, and proposes Selective Cooperation, where the selection criteria is based on throughput.
Abstract: Cooperative transmission schemes are used in wireless networks to improve the spectral efficiency. In a multi-cell environment, inter-cell interference degrades the performance of wireless systems. In this paper, we study the downlink capacity of edge users in a cellular network and see whether base station cooperation improves the spectral efficiency. The base-stations coordinate their transmission to the two cell-edge users in order to improve their Signal-to-interference-noise ratio (SINR) and throughput. Selective Cooperation, where the selection criteria is based on throughput, is proposed. The capacity achieved through Cooperation is shared equally among the cell-edge users. Results show that, the proposed hybrid scheme, provides a better result compared to full-time cooperation. Finally, an example from UMTS is presented.
TL;DR: The normal operation, full cooperation and distinct cooperation scheme in the downlink environment for cell edge users in cellular network is analyzed and it is compared and seen which method improves the user capacity and data rate.
Abstract: In a conventional cellular network, a terminal receives signals not only from the base station of that cell, but also from other cell base stations. This inter-cell interference has more impact on the cell-edge users, in multi cell environment. The inter-cell interference degrades the performance of wireless systems. Using Base Station Cooperation, the ability of a mobile station to receive signals from multiple base stations can be utilized as an opportunity to improve the spectral efficiency and to get higher data rates for cell edge users. In multi cell environment using base station cooperation overall interference can be minimized marginally, whereas the interference within the cooperation region is largely reduced. This leads to a question whether it is worth doing cooperation all the time. However increase in terms of throughput may not always be enough to increase the throughput of each of the user .Hence for such a scenario the distinct cooperation scheme is used. The distinct cooperation is a joint transmission scheme in which the selection criterion is based on user’s signal to interference plus noise ratio (SINR) is proposed and the capacity achieved through cooperation is shared equally among the cell-edge users. Here we will analyze the normal operation, full cooperation and distinct cooperation scheme in the downlink environment for cell edge users in cellular network and we will compare and see which method improves the user capacity and data rate.
Cites background or methods from "Throughput improvement for cell-edg..."
...System model [7] The received signal at MS1 and MS2 are y1 and y2, and is given by equation 5....
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...In this paper, We therefore analyze the preferred cooperation scheme which is a hybrid scheme that adds low complexity, in order to keep the exchange of channel state information between base stations low [7]....
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...zi is the total interference received by MS i due to transmissions from all the base stations other than the one under cooperation (Here BS2) and ni is the additive white Gaussian noise, zi is the interference [7]....
TL;DR: This letter studies cell cooperation in the downlink OFDMA cellular networks based on fractional frequency reuse (FFR), where a cooperation group consists of three sector antennas from three adjacent cells and the subchannels of each cooperation group are allocated coordinately to users.
Abstract: SUMMARY In this letter, we study cell cooperation in the downlinkOFDMA cellular networks. The proposed cooperation scheme is based onfractional frequency reuse (FFR), where a cooperation group consists ofthree sector antennas from three adjacent cells and the subchannels of eachcooperation group are allocated coordinately to users. Simulation resultsdemonstrate the effectiveness of the proposed schemes in terms of through-put and fairness. key words: multi-cell cooperation, OFDMA, FFR, ICI coordination, fair-ness 1. Introduction As an advanced physical layer technology, OFDMA hasbeen proposed by 3GPP LTE (3rd Generation PartnershipProject Long Term Evolution) to be the multiple accesstech-nique for the downlink in B3G (Beyond 3rd Generation)systems [1]. In the OFDMA-based cellular system, the sub-channels used within a cell are orthogonal to each other suchthat the interference can be avoided. However, the users onthe border of the cell not only receive signals from the serv-ing base station (BS), but also suffer severe inter cell inter-ference (ICI) from the neighboring cells which use the sameset of subchannels. The so called ICI will degenerate thesystem performance and must be mitigated.In 3GPP LTE, three approaches have been proposed tomitigate the so-called ICI, i.e., ICI randomization, ICI coor-dination, and ICI cancelation. Among the three approaches,ICI coordination is comparatively easier to be realized andcan be used in various wide band traffics [2]. The basicidea behind ICI coordination is exploiting FFR techniqueto separate the interfering source as far as possible whileincreasing spectral efficiency as much as possible [3],[4].FFR relies on partitioning the total available frequency re-source into two sets and dividing a cell into two concentricregion, namely, interior region and exterior region. One setof the frequency is used by users in the interior region of allcells with a frequency reuse factor (FRF) of 1. While the
TL;DR: This paper presents the cooperation scenario which improves the performance of signal and calculates the signal capacity using the following schemes without cooperation, with full and hybrid cooperation.
Abstract: The strength of signal becomes weak as it reaches the edge of a cell. The performance degrades due to inter-cell interference. In this paper, we present the cooperation scenario which improves this performance and calculate the signal capacity using the following schemes without cooperation, with full and hybrid cooperation General Terms Base station cooperation
TL;DR: A scheduling algorithm, called Power-aware Opportunistic Downlink Scheduling (PODS), that aims at meeting both the QoS and fairness requirements, while taking into account the different power levels of the bandwidth chunks.
TL;DR: Results show that, even though the interuser channel is noisy, cooperation leads not only to an increase in capacity for both users but also to a more robust system, where users' achievable rates are less susceptible to channel variations.
Abstract: Mobile users' data rate and quality of service are limited by the fact that, within the duration of any given call, they experience severe variations in signal attenuation, thereby necessitating the use of some type of diversity. In this two-part paper, we propose a new form of spatial diversity, in which diversity gains are achieved via the cooperation of mobile users. Part I describes the user cooperation strategy, while Part II (see ibid., p.1939-48) focuses on implementation issues and performance analysis. Results show that, even though the interuser channel is noisy, cooperation leads not only to an increase in capacity for both users but also to a more robust system, where users' achievable rates are less susceptible to channel variations.
6,621 citations
"Throughput improvement for cell-edg..." refers background in this paper
...Cooperative transmission utilizes the inherent user diversity available in a multi-user environment to provide higher spectral efficiency [1–3]....
TL;DR: An overview of the developments in cooperative communication, a new class of methods called cooperative communication has been proposed that enables single-antenna mobiles in a multi-user environment to share their antennas and generate a virtual multiple-antenn transmitter that allows them to achieve transmit diversity.
Abstract: Transmit diversity generally requires more than one antenna at the transmitter. However, many wireless devices are limited by size or hardware complexity to one antenna. Recently, a new class of methods called cooperative communication has been proposed that enables single-antenna mobiles in a multi-user environment to share their antennas and generate a virtual multiple-antenna transmitter that allows them to achieve transmit diversity. This article presents an overview of the developments in this burgeoning field.
3,130 citations
"Throughput improvement for cell-edg..." refers background in this paper
...Cooperative transmission utilizes the inherent user diversity available in a multi-user environment to provide higher spectral efficiency [1–3]....
TL;DR: Two variants of an energy-efficient cooperative diversity protocol are developed that combats fading induced by multipath propagation in wireless networks and can lead to reduced battery drain, longer network lifetime, and improved network performance in terms of, e.g., capacity.
Abstract: We develop two variants of an energy-efficient cooperative diversity protocol that combats fading induced by multipath propagation in wireless networks, The underlying techniques build upon the classical relay channel and related work and exploit space diversity available at distributed antennas through coordinated transmission and processing by cooperating radios. While applicable to any wireless setting, these protocols are particularly attractive in ad-hoc or peer-to-peer wireless networks, in which radios are typically constrained to employ a single antenna. Substantial energy-savings resulting from these protocols can lead to reduced battery drain, longer network lifetime, and improved network performance in terms of, e.g., capacity.
688 citations
"Throughput improvement for cell-edg..." refers background in this paper
...Cooperative transmission utilizes the inherent user diversity available in a multi-user environment to provide higher spectral efficiency [1–3]....
TL;DR: Holma et al. as mentioned in this paper proposed a radio resource management architecture for HSDPA and showed that HSUPA bit rates, capacity and coverage can be improved by using IP header compression.
Abstract: Preface. Acknowledgements. Abbreviations. 1. Introduction (Harri Holma and Antti Toskala). 1.1 WCDMA technology and deployment status. 1.2 HSPA standardization and deployment schedule. 1.3 Radio capability evolution with HSPA. 2. HSPA standardization and background (Antti Toskala and Karri Ranta-Aho) 2.1 3GPP. 2.2 References. 3. HSPA architecture and protocols (Antti Toskala and Juho Pirskanen). 3.1 Radio resource management architecture. 3.2 References. 4. HSDPA principles (Juho Pirskanen and Antti Toskala). 4.1 HSDPA vs Release 99 DCH. 4.2 Key technologies with HSDPA. 4.3 High-speed dedicated physical control channel. 4.4 BTS measurements for HSDPA operation. 4.5 Terminal capabilities. 4.6 HSDPA MAC layer operation. 4.7 References. 5. HSUPA principles (Karri Ranta-Aho and Antti Toskala). 5.1 HSUPA vs Release 99 DCH. 5.2 Key technologies with HSUPA. 5.3 E-DCH transport channel and physical channels. 5.4 Physical layer procedures. 5.5 MAC layer. 5.6 Iub parameters. 5.7 Mobility. 5.8 UE capabilities and data rates. 5.9 References and list of related 3GPP specifications. 6. Radio resource management (Harri Holma, Troels Kolding, Klaus Pedersen, and Jeroen Wigard). 6.1 HSDPA radio resource management. 6.2 HSUPA radio resource management. 6.3 References. 7. HSDPA bit rates, capacity and coverage (Frank Frederiksen, Harri Holma, Troels Kolding, and Klaus Pedersen). 7.1 General performance factors. 7.2 Single-user performance. 7.3 Multiuser system performance. 7.4 Iub transmission efficiency. 7.5 Capacity and cost of data delivery. 7.6 Round trip time. 7.7 HSDPA measurements. 7.8 HSDPA performance evolution. 7.9 Conclusions. 7.10 Bibliography. 8. HSUPA bit rates, capacity and coverage (Jussi Jaatinen, Harri Holma, Claudio Rosa, and Jeroen Wigard). 8.1 General performance factors. 8.2 Single-user performance. 8.3 Cell capacity. 8.4 HSUPA performance enhancements. 8.5 Conclusions. 8.6 Bibliography. 9. Application and end-to-end performance (Chris Johnson, Sandro Grech, Harri Holma, and Martin Kristensson) 9.1 Packet application introduction. 9.2 Always-on connectivity. 9.3 Application performance over HSPA. 9.4 Application performance vs network load. 9.5 References. 10. Voice-over-IP (Harri Holma, Esa Malkama ki, and Klaus Pedersen). 10.1 VoIP motivation. 10.2 IP header compression. 10.3 VoIP over HSPA. 10.4 References. 11. RF requirements of an HSPA terminal (Harri Holma, Jussi Numminen, Markus Pettersson, and Antti Toskala). 11.1 Transmitter requirements. 11.2 Receiver requirements. 11.3 Frequency bands and multiband terminals. 11.4 References. Index.
TL;DR: It is argued that many of the traditional interference management techniques have limited usefulness when viewed in concert with MIMO, and emerging system-level interference-reducing strategies based on cooperation will be important for overcoming interference in future spatial multiplexing cellular systems.
Abstract: Multi-antenna transmission and reception (known as MIMO) is widely touted as the key technology for enabling wireless broadband services, whose widespread success will require 10 times higher spectral efficiency than current cellular systems, at 10 times lower cost per bit. Spectrally efficient, inexpensive cellular systems are by definition densely populated and interference-limited. But spatial multiplexing MIMO systems- whose principal merit is a supposed dramatic increase in spectral efficiency- lose much of their effectiveness in high levels of interference. This article overviews several approaches to handling interference in multicell MIMO systems. The discussion is applicable to any multi-antenna cellular network, including 802.16e/WiMAX, 3GPP (HSDPA and 3GPP LTE), and 3GPP2 (lxEVDO). We argue that many of the traditional interference management techniques have limited usefulness (or are even counterproductive) when viewed in concert with MIMO. The problem of interference in MIMO systems is too large in scope to be handled with a single technique: in practice a combination of complementary countermeasures will be needed. We overview emerging system-level interference-reducing strategies based on cooperation, which will be important for overcoming interference in future spatial multiplexing cellular systems.
383 citations
"Throughput improvement for cell-edg..." refers methods in this paper
...Cooperative encoding and scheduling in a Networked MIMO system is discussed in [6], in order to supress Other Cell Interference (OCI) and thereby achieve maximum capacity in MIMO downlink channel....