| 1. |
- Huang, Yezi, et al.
(författare)
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Enabling DSL and Radio on the Same Copper Pair
- 2015
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Ingår i: 2015 IEEE International Conference on Communications (ICC). - 9781467364324 ; , s. 1031-1035
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Konferensbidrag (refereegranskat)abstract
- To increase indoor coverage for mobile services, we propose a residential small cell infrastructure making use of the existing copper plant. The system is cabinet-based, collocated with VDSL2 and uses small pieces of spectrum next to VDSL2. Inspired by the Ericsson Radio Dot System, it challenges the femtocell paradigm offering full macro functionality in the small cells. An interesting service potential is offered albeit the added mobile traffic capacity is moderate as it is limited by the copper fronthaul.
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| 2. |
- Huang, Yezi, et al.
(författare)
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LTE Over Copper - Potential and Limitations
- 2015
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Ingår i: 2015 IEEE 26th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC). - 9781467367820 ; , s. 1339-1343
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Konferensbidrag (refereegranskat)abstract
- The densification of mobile networks in order to meet increased capacity demands is ongoing, needed and costly. A few papers have been published based on the insight that the fixed broadband networks offer a multitude of sites, for instance our homes, for potential small cell deployment providing backhaul capacity and power without site costs. However, in order to reach economical large-scale benefits, we explore the case when radio systems are deployed in coexistence with DSL. In this paper, we establish the feasibility of such a concept under constraints invoked by state-of-the-art and emerging systems (3GPP, VDSL2 and G.fast) and make statements about the required architecture. We also point out that the enthusiasm of previously published results should be lowered a notch.
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| 3. |
- Huang, Yezi, et al.
(författare)
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Time-Domain Precoding for LTE-over-Copper Systems
- 2016
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Ingår i: 2016 IEEE International Conference on Communications (ICC). - 9781479966646 - 9781479966653 ; , s. 1-6
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Konferensbidrag (refereegranskat)abstract
- Crosstalk cancellation is a crucial issue for traditional digital subscriber line systems. For LTE-over-copper systems, however, the need for crosstalk cancellation varies depending on the analog fronthauling architecture and its parameters. A crosstalk handler that is decoupled as much as possible from the rest of the system architecture is thus preferred. Therefore, we propose a time-domain precoding scheme specifically in downstream direction to separate the precoding unit from the LTE signal flow, and perform crosstalk cancellation in an on-demand manner. Estimation of all direct and crosstalk paths is assisted by LTE cell-specific reference signals. The time-domain precoder transforms the interference channel into a crosstalk-free channel with identical direct paths, which allows for low-complexity inter-symbol interference mitigation. We evaluate the concept in terms of signal-to-noise ratio provided for LTE signals using measured wireline channel data.
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| 4. |
- Medeiros, Eduardo, et al.
(författare)
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Crosstalk Mitigation for LTE-over-Copper in Downlink Direction
- 2016
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Ingår i: IEEE Communications Letters. - 1089-7798. ; 20:7, s. 1425-1428
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Tidskriftsartikel (refereegranskat)abstract
- Radio-over-copper is a niche idea that has potential to become a cornerstone in the deployment of dense 5G networks. We address one of the remaining hurdles and present an architecture for transparent crosstalk mitigation in LTE-over-copper systems. By taking advantage of reference symbols present in the downlink LTE signals we propose two methods for estimating the copper channel. System performance is evaluated using channel measurements and error vector magnitude calculations with promising results.
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| 5. |
- Acatauassu, Diogo, et al.
(författare)
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KHM cable model parameters for ITU-T G.Fast reference loops
- 2016
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Ingår i: 2015 IEEE Conference on Standards for Communications and Networking, CSCN 2015. - 9781479989287 ; , s. 168-173
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Konferensbidrag (refereegranskat)abstract
- G.Fast is a new standard for fixed broadband access that aims at achieving bit rates of 1 Gb/s over short copper loops. In order to give support to simulation, design and performance evaluation tests, the G.Fast recommendation presents examples of some wiring topologies and reference loops describing configurations expected to be found in real G.Fast deployments. Our work describes results of modeling some types of lines adopted in these reference loops by means of a low complexity and causal parametric cable model. The results indicate that the modeling approach proposed in this work is accurate for all the analyzed cases, which include high quality, medium quality and low quality cables.
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| 6. |
- Andgart, Niklas, et al.
(författare)
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Designing tone reservation PAR reduction
- 2006
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Ingår i: Eurasip Journal on Applied Signal Processing. - 1110-8657.
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Tidskriftsartikel (refereegranskat)abstract
- Tone reservation peak-to-average ( PAR) ratio reduction is an established area when it comes to bringing down signal peaks inmulticarrier (DMT or OFDM) systems. When designing such a system, some questions often arise about PAR reduction. Is it worth the effort? How much can it give? How much does it give depending on the parameter choices? With this paper, we attempt to answer these questions without resolving to extensive simulations for every system and every parameter choice. From a specification of the allowed spectrum, for instance prescribed by a standard, including a PSD-mask and a number of tones, we analytically predict achievable PAR levels, and thus implicitly suggest parameter choices. We use the ADSL2 and ADSL2+ systems as design examples.
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| 7. |
- Andgart, Niklas, et al.
(författare)
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PSD-constrained PAR reduction for DMT/OFDM
- 2004
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Ingår i: Eurasip Journal on Applied Signal Processing. - 1110-8657. ; 2004:10
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Tidskriftsartikel (refereegranskat)abstract
- Common to all DMT/OFDM systems is a large peak-to-average ratio (PAR), which can lead to low power efficiency and nonlinear distortion. Tone reservation uses unused or reserved tones to design a peak-canceling signal to lower the PAR of a transmit block. In DMT ADSL systems, the power allocated to these tones may be limited due to crosstalk issues with many users in one twisted pair bundle. This PSD limitation not only limits PAR reduction ability, but also makes the optimization problem more challenging to solve. Extending the recently proposed active set tone reservation method, we develop an efficient algorithm with performance close to the optimal solution.
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| 8. |
- Bengtsson, Daniel, et al.
(författare)
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Trellis coding in a discrete multitone modulation system
- 1996
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Ingår i: Proceedings of the 1996 SNRV and NUTEK Conference on Radio Sciences and Telecommunications in Luleå and Kiruna June 3-6, 1996. - Luleå : Luleå tekniska universitet. - 9163044552 ; , s. 668-672
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Konferensbidrag (refereegranskat)abstract
- Discrete Multitone (DMT) modulation is a multicarrier technique which makes efficient use of the channel, maximizing the throughput by sending different numbers of bits on different subchannels. The number of bits on each subchannel depends on the Signal-to-Noise Ratio of the subchannel. The performance of a DMT system can be further increased by using powerful coding techniques. This paper investigates an implementation of trellis coded modulation in a DMT system intended for transmission over short copper cables, less than 1000m. We suggested trellis code is Wei's 4-dimensional 16-state coder combined with trellis shaping. A single encoder is used which codes across the tones of each DMT-symbol. At a bit error probability of 10-7, the suggested code gains 4-5 dB over uncoded transmission.
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| 9. |
- Börjesson, Per Ola, et al.
(författare)
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A low-complexity PAR-reduction method for DMT-VDSL
- 1999
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Ingår i: Proceedings of the 5th International Symposium on Digital Signal Processing for Communication Systems. ; , s. 164-169
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Konferensbidrag (refereegranskat)abstract
- DMT-VDSL signals have a high peak-to-average power ratio (PAR). In the transmitters, the PAR governs the necessary resolution of the digital-to-analog converter (DAC) and is an important factor for the power consumption of the line-driver. Aiming at implementation in a specific system, we propose a low complexity PAR-reduction method based on the iterative algorithm derived in [5, 20, 24, 25]. We maintain good performance while stressing a straigthforward and low-complex implementation. Key elements of the method are: low latency; no loss in data rate; precalculated and stored peak-cancellation waveform; and bit-shifts (multiplication with powers of two) replacing the scaling of the waveform. Computer simulations show that, for a DMT frame length of 4096 samples and a frame clip rate of 10-4, the PAR can be reduced about 1.5 to 2.0 dB, depending on the number of peaks cancelled. When multiplication is replaced by bit-shifts, the reduction is still 1.5-1.7 dB.
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| 10. |
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