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    ์ฐจ์„ธ๋Œ€ ์ž๋™์ฐจ์šฉ ์นด๋ฉ”๋ผ ๋ฐ์ดํ„ฐ ํ†ต์‹ ์„ ์œ„ํ•œ ๋น„๋Œ€์นญ ๋™์‹œ ์–‘๋ฐฉํ–ฅ ์†ก์ˆ˜์‹ ๊ธฐ์˜ ์„ค๊ณ„

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    ํ•™์œ„๋…ผ๋ฌธ(๋ฐ•์‚ฌ) -- ์„œ์šธ๋Œ€ํ•™๊ต๋Œ€ํ•™์› : ๊ณต๊ณผ๋Œ€ํ•™ ์ „๊ธฐยท์ •๋ณด๊ณตํ•™๋ถ€, 2022.2. ์ •๋•๊ท .๋ณธ ํ•™์œ„ ๋…ผ๋ฌธ์—์„œ๋Š” ์ฐจ์„ธ๋Œ€ ์ž๋™์ฐจ์šฉ ์นด๋ฉ”๋ผ ๋งํฌ๋ฅผ ์œ„ํ•ด ๋†’์€ ์†๋„์˜ 4๋ ˆ๋ฒจ ํŽ„์Šค ์ง„ํญ ๋ณ€์กฐ ์‹ ํ˜ธ์™€ ๋‚ฎ์€ ์†๋„์˜ 2๋ ˆ๋ฒจ ํŽ„์Šค ์ง„ํญ ๋ณ€์กฐ ์‹ ํ˜ธ๋ฅผ ํ†ต์‹ ํ•˜๋Š” ๋น„๋Œ€์นญ ๋™์‹œ ์–‘๋ฐฉํ–ฅ ์†ก์ˆ˜์‹ ๊ธฐ์˜ ์„ค๊ณ„ ๊ธฐ์ˆ ์— ๋Œ€ํ•ด ์ œ์•ˆํ•˜๊ณ  ๊ฒ€์ฆ๋˜์—ˆ๋‹ค. ์ฒซ๋ฒˆ์งธ ํ”„๋กœํ† ํƒ€์ž… ์„ค๊ณ„์—์„œ๋Š”, 10B6Q ์ง๋ฅ˜ ๋ฐธ๋Ÿฐ์Šค ์ฝ”๋“œ๋ฅผ ํƒ‘์žฌํ•œ 4๋ ˆ๋ฒจ ํŽ„์Šค ์ง„ํญ ๋ณ€์กฐ ์†ก์‹ ๊ธฐ์™€ ๊ณ ์ •๋œ ๋ฐ์ดํ„ฐ์™€ ์ฐธ์กฐ ๋ ˆ๋ฒจ์„ ๊ฐ€์ง€๋Š” 4๋ ˆ๋ฒจ ํŽ„์Šค ์ง„ํญ ๋ณ€์กฐ ์ ์‘ํ˜• ์ˆ˜์‹ ๊ธฐ์— ๋Œ€ํ•œ ๋‚ด์šฉ์ด ๊ธฐ์ˆ ๋˜์—ˆ๋‹ค. 4๋ ˆ๋ฒจ ํŽ„์Šค ์ง„ํญ ๋ณ€์กฐ ์†ก์‹ ๊ธฐ์—์„œ๋Š” ๊ต๋ฅ˜ ์—ฐ๊ฒฐ ๋งํฌ ์‹œ์Šคํ…œ์— ๋Œ€์‘ํ•˜๊ธฐ ์œ„ํ•œ ๋ฉด์  ๋ฐ ์ „๋ ฅ ํšจ์œจ์„ฑ์ด ์ข‹์€ 10B6Q ์ฝ”๋“œ๊ฐ€ ์ œ์•ˆ๋˜์—ˆ๋‹ค. ์ด ์ฝ”๋“œ๋Š” ์ง๋ฅ˜ ๋ฐธ๋Ÿฐ์Šค๋ฅผ ๋งž์ถ”๊ณ  ์—ฐ์†์ ์œผ๋กœ ๊ฐ™์€ ์‹ฌ๋ณผ์„ ๊ฐ€์ง€๋Š” ๊ธธ์ด๋ฅผ 6๊ฐœ๋กœ ์ œํ•œ ์‹œํ‚จ๋‹ค. ๋น„๋ก ์—ฌ๊ธฐ์„œ๋Š” ์ž…๋ ฅ ๋ฐ์ดํ„ฐ ๊ธธ์ด 10๋น„ํŠธ๋ฅผ ์‚ฌ์šฉํ•˜์˜€์ง€๋งŒ, ์ œ์•ˆ๋œ ๊ธฐ์ˆ ์€ ์นด๋ฉ”๋ผ์˜ ๋‹ค์–‘ํ•œ ๋ฐ์ดํ„ฐ ํƒ€์ž…์— ๋Œ€์‘ํ•  ์ˆ˜ ์žˆ๋„๋ก ์ž…๋ ฅ ๋ฐ์ดํ„ฐ ๊ธธ์ด์— ๋Œ€ํ•œ ํ™•์žฅ์„ฑ์„ ๊ฐ€์ง„๋‹ค. ๋ฐ˜๋ฉด, 4๋ ˆ๋ฒจ ํŽ„์Šค ์ง„ํญ ๋ณ€์กฐ ์ ์‘ํ˜• ์ˆ˜์‹ ๊ธฐ์—์„œ๋Š”, ์ƒ˜ํ”Œ๋Ÿฌ์˜ ์˜ต์…‹์„ ์ตœ์ ์œผ๋กœ ์ œ๊ฑฐํ•˜์—ฌ ๋” ๋‚ฎ์€ ๋น„ํŠธ์—๋Ÿฌ์œจ์„ ์–ป๊ธฐ ์œ„ํ•ด์„œ, ๊ธฐ์กด์˜ ๋ฐ์ดํ„ฐ ๋ฐ ์ฐธ์กฐ ๋ ˆ๋ฒจ์„ ์กฐ์ ˆํ•˜๋Š” ๋Œ€์‹ , ์ด ๋ ˆ๋ฒจ๋“ค์€ ๊ณ ์ •์‹œํ‚ค๊ณ  ๊ฐ€๋ณ€ ๊ฒŒ์ธ ์ฆํญ๊ธฐ๋ฅผ ์ ์‘ํ˜•์œผ๋กœ ์กฐ์ ˆํ•˜๋„๋ก ํ•˜์˜€๋‹ค. ์ƒ๊ธฐ 10B6Q ์ฝ”๋“œ ๋ฐ ๊ณ ์ • ๋ฐ์ดํ„ฐ ๋ฐ ์ฐธ์กฐ๋ ˆ๋ฒจ ๊ธฐ์ˆ ์„ ๊ฐ€์ง„ ํ”„๋กœํ† ํƒ€์ž… ์นฉ๋“ค์€ 40 ๋‚˜๋…ธ๋ฏธํ„ฐ ์ƒํ˜ธ๋ณด์™„ํ˜• ๋ฉ”ํƒˆ ์‚ฐํ™” ๋ฐ˜๋„์ฒด ๊ณต์ •์œผ๋กœ ์ œ์ž‘๋˜์—ˆ๊ณ  ์นฉ ์˜จ ๋ณด๋“œ ํ˜•ํƒœ๋กœ ํ‰๊ฐ€๋˜์—ˆ๋‹ค. 10B6Q ์ฝ”๋“œ๋Š” ํ•ฉ์„ฑ ๊ฒŒ์ดํŠธ ์ˆซ์ž๋Š” 645๊ฐœ์™€ ํ•จ๊ป˜ ๋‹จ 0.0009 mm2 ์˜ ๋ฉด์  ๋งŒ์„ ์ฐจ์ง€ํ•œ๋‹ค. ๋˜ํ•œ, 667 MHz ๋™์ž‘ ์ฃผํŒŒ์ˆ˜์—์„œ ๋‹จ 0.23 mW ์˜ ์ „๋ ฅ์„ ์†Œ๋ชจํ•œ๋‹ค. 10B6Q ์ฝ”๋“œ๋ฅผ ํƒ‘์žฌํ•œ ์†ก์‹ ๊ธฐ์—์„œ 8-Gb/s 4๋ ˆ๋ฒจ ํŽ„์Šค ์ง„ํญ ๋ณ€์กฐ ์‹ ํ˜ธ๋ฅผ ๊ณ ์ • ๋ฐ์ดํ„ฐ ๋ฐ ์ฐธ์กฐ ๋ ˆ๋ฒจ์„ ๊ฐ€์ง€๋Š” ์ ์‘ํ˜• ์ˆ˜์‹ ๊ธฐ๋กœ 12-m ์ผ€์ด๋ธ” (22-dB ์ฑ„๋„ ๋กœ์Šค) ์„ ํ†ตํ•ด์„œ ๋ณด๋‚ธ ๊ฒฐ๊ณผ ์ตœ์†Œ ๋น„ํŠธ ์—๋Ÿฌ์œจ 108 ์„ ๋‹ฌ์„ฑํ•˜์˜€๊ณ , ๋น„ํŠธ ์—๋Ÿฌ์œจ 105 ์—์„œ๋Š” ์•„์ด ๋งˆ์ง„์ด 0.15 UI x 50 mV ๋ณด๋‹ค ํฌ๊ฒŒ ์ธก์ •๋˜์—ˆ๋‹ค. ์†ก์ˆ˜์‹ ๊ธฐ๋ฅผ ํ•ฉ์นœ ์ „๋ ฅ ์†Œ๋ชจ๋Š” 65.2 mW (PLL ์ œ์™ธ) ์ด๊ณ , ์„ฑ๊ณผ์˜ ๋Œ€ํ‘œ์ˆ˜์น˜๋Š” 0.37 pJ/b/dB ๋ฅผ ๋ณด์—ฌ์ฃผ์—ˆ๋‹ค. ์ฒซ๋ฒˆ์งธ ํ”„๋กœํ† ํƒ€์ž… ์„ค๊ณ„์„ ํฌํ•จํ•˜์—ฌ ๊ฐœ์„ ๋œ ๋‘๋ฒˆ์งธ ํ”„๋กœํ† ํƒ€์ž… ์„ค๊ณ„์—์„œ๋Š”, 12-Gb/s 4๋ ˆ๋ฒจ ํŽ„์Šค ์ง„ํญ ๋ณ€์กฐ ์ •๋ฐฉํ–ฅ ์ฑ„๋„ ์‹ ํ˜ธ์™€ 125-Mb/s 2๋ ˆ๋ฒจ ํŽ„์Šค ์ง„ํญ ๋ณ€์กฐ ์—ญ๋ฐฉํ–ฅ ์ฑ„๋„ ์‹ ํ˜ธ๋ฅผ ํƒ‘์žฌํ•œ ๋น„๋Œ€์นญ ๋™์‹œ ์–‘๋ฐฉํ–ฅ ์†ก์ˆ˜์‹ ๊ธฐ์— ๋Œ€ํ•ด ๊ธฐ์ˆ ๋˜๊ณ  ๊ฒ€์ฆ๋˜์—ˆ๋‹ค. ์ œ์•ˆ๋œ ๋„“์€ ์„ ํ˜• ๋ฒ”์œ„๋ฅผ ๊ฐ€์ง€๋Š” ํ•˜์ด๋ธŒ๋ฆฌ๋“œ๋Š” gmC ์ €๋Œ€์—ญ ํ†ต๊ณผ ํ•„ํ„ฐ์™€ ์—์ฝ” ์ œ๊ฑฐ๊ธฐ์™€ ํ•จ๊ป˜ ์•„์›ƒ๋ฐ”์šด๋“œ ์‹ ํ˜ธ๋ฅผ 24 dB ์ด์ƒ ํšจ์œจ์ ์œผ๋กœ ๊ฐ์†Œ์‹œ์ผฐ๋‹ค. ๋˜ํ•œ, ๋„“์€ ์„ ํ˜• ๋ฒ”์œ„๋ฅผ ๊ฐ€์ง€๋Š” ํ•˜์ด๋ธŒ๋ฆฌ๋“œ์™€ ํ•จ๊ป˜ ๊ฒŒ์ธ ๊ฐ์†Œ๊ธฐ๋ฅผ ํ˜•์„ฑํ•˜๊ฒŒ ๋˜๋Š” ์„ ํ˜• ๋ฒ”์œ„ ์ฆํญ๊ธฐ๋ฅผ ํ†ตํ•ด 4๋ ˆ๋ฒจ ํŽ„์Šค ์ง„ํญ ๋ณ€์กฐ ์‹ ํ˜ธ์˜ ์„ ํ˜•์„ฑ๊ณผ ์ง„ํญ์˜ ํŠธ๋ ˆ์ด๋“œ ์˜คํ”„ ๊ด€๊ณ„๋ฅผ ๊นจ๋Š” ๊ฒƒ์ด ๊ฐ€๋Šฅํ•˜์˜€๋‹ค. ๋™์‹œ ์–‘๋ฐฉํ–ฅ ์†ก์ˆ˜์‹ ๊ธฐ ์นฉ์€ 40 ๋‚˜๋…ธ๋ฏธํ„ฐ ์ƒํ˜ธ๋ณด์™„ํ˜• ๋ฉ”ํƒˆ ์‚ฐํ™” ๋ฐ˜๋„์ฒด ๊ณต์ •์œผ๋กœ ์ œ์ž‘๋˜์—ˆ๋‹ค. ์ƒ๊ธฐ ์„ค๊ณ„ ๊ธฐ์ˆ ๋“ค์„ ์ด์šฉํ•˜์—ฌ, 4๋ ˆ๋ฒจ ํŽ„์Šค ์ง„ํญ ๋ณ€์กฐ ๋ฐ 2๋ ˆ๋ฒจ ํŽ„์Šค ์ง„ํญ ๋ณ€์กฐ ์†ก์ˆ˜์‹ ๊ธฐ ๋ชจ๋‘ 5m ์ฑ„๋„ (์ฑ„๋„ ๋กœ์Šค 15.9 dB) ์—์„œ 1E-12 ๋ณด๋‹ค ๋‚ฎ์€ ๋น„ํŠธ ์—๋Ÿฌ์œจ์„ ๋‹ฌ์„ฑํ•˜์˜€๊ณ , ์ด 78.4 mW ์˜ ์ „๋ ฅ ์†Œ๋ชจ๋ฅผ ๊ธฐ๋กํ•˜์˜€๋‹ค. ์ข…ํ•ฉ์ ์ธ ์†ก์ˆ˜์‹ ๊ธฐ๋Š” ์„ฑ๊ณผ ๋Œ€ํ‘œ์ง€ํ‘œ๋กœ 0.41 pJ/b/dB ์™€ ํ•จ๊ป˜ ๋™์‹œ ์–‘๋ฐฉํ–ฅ ํ†ต์‹  ์•„๋ž˜์—์„œ 4๋ ˆ๋ฒจ ํŽ„์Šค ์ง„ํญ ๋ณ€์กฐ ์‹ ํ˜ธ ๋ฐ 2๋ ˆ๋ฒจ ํŽ„์Šค ์ง„ํญ ๋ณ€์กฐ ์‹ ํ˜ธ ๊ฐ๊ฐ์—์„œ ์•„์ด ๋งˆ์ง„ 0.15 UI ์™€ 0.57 UI ๋ฅผ ๋‹ฌ์„ฑํ•˜์˜€๋‹ค. ์ด ์ˆ˜์น˜๋Š” ์„ฑ๊ณผ ๋Œ€ํ‘œ์ง€ํ‘œ 0.5 ์ดํ•˜๋ฅผ ๊ฐ€์ง€๋Š” ๊ธฐ์กด ๋™์‹œ ์–‘๋ฐฉํ–ฅ ์†ก์ˆ˜์‹ ๊ธฐ์™€์˜ ๋น„๊ต์—์„œ ์ตœ๊ณ ์˜ ์•„์ด ๋งˆ์ง„์„ ๊ธฐ๋กํ•˜์˜€๋‹ค.In this dissertation, design techniques of a highly asymmetric simultaneous bidirectional (SB) transceivers with high-speed PAM-4 and low-speed PAM-2 signals are proposed and demonstrated for the next-generation automotive camera link. In a first prototype design, a PAM-4 transmitter with 10B6Q DC balance code and a PAM-4 adaptive receiver with fixed data and threshold levels (dtLevs) are presented. In PAM-4 transmitter, an area- and power-efficient 10B6Q code for an AC coupled link system that guarantees DC balance and limited run length of six is proposed. Although the input data width of 10 bits is used here, the proposed scheme has an extensibility for the input data width to cover various data types of the camera. On the other hand, in the PAM-4 adaptive receiver, to optimally cancel the sampler offset for a lower BER, instead of adjusting dtLevs, the gain of a programmable gain amplifier is adjusted adaptively under fixed dtLevs. The prototype chips including above proposed 10B6Q code and fixed dtLevs are fabricated in 40-nm CMOS technology and tested in chip-on-board assembly. The 10B6Q code only occupies an active area of 0.0009 mm2 with a synthesized gate count of 645. It also consumes 0.23 mW at the operating clock frequency of 667 MHz. The transmitter with 10B6Q code delivers 8-Gb/s PAM-4 signal to the adaptive receiver using fixed dtLevs through a lossy 12-m cable (22-dB channel loss) with a BER of 1E-8, and the eye margin larger than 0.15 UI x 50 mV is measured for a BER of 1E-5. The proto-type chips consume 65.2 mW (excluding PLL), exhibiting an FoM of 0.37 pJ/b/dB. In a second prototype design advanced from the first prototypes, An asymmetric SB transceivers incorporating a 12-Gb/s PAM-4 forward channel and a 125-Mb/s PAM-2 back channel are presented and demonstrated. The proposed wide linear range (WLR) hybrid combined with a gmC low-pass filter and an echo canceller effectively suppresses the outbound signals by more than 24dB. In addition, linear range enhancer which forms a gain attenuator with WLR hybrid breaks the trade-off between the linearity and the amplitude of the PAM-4 signal. The SB transceiver chips are separately fabricated in 40-nm CMOS technology. Using above design techniques, both PAM-4 and PAM-2 SB transceivers achieve BER less than 1E-12 over a 5-m channel (15.9 dB channel loss), consuming 78.4 mW. The overall transceivers achieve an FoM of 0.41 pJ/b/dB and eye margin (at BER of 1E-12) of 0.15 UI and 0.57 UI for the forward PAM-4 and back PAM-2 signals, respectively, under SB communication. This is the best eye margin compared to the prior art SB transceivers with an FoM less than 0.5.CHAPTER 1 INTRODUCTION 1 1.1 MOTIVATION 1 1.2 DISSERTATION ORGANIZATION 4 CHAPTER 2 BACKGROUND ON AUTOMOTIVE CAMERA LINK 6 2.1 OVERVIEW 6 2.2 SYSTEM REQUIREMENTS 10 2.2.1 CHANNEL 10 2.2.2 POWER OVER DIFFERENTIAL LINE (PODL) 12 2.2.3 AC COUPLING AND DC BALANCE CODE 15 2.2.4 SIMULTANEOUS BIDIRECTIONAL COMMUNICATION 18 2.2.4.1 HYBRID 18 2.2.4.2 ECHO CANCELLER 20 2.2.5 ADAPTIVE RECEIVE EQUALIZATION 22 CHAPTER 3 AREA AND POWER EFFICIENT 10B6Q ENCODER FOR DC BALANCE 25 3.1 INTRODUCTION 25 3.2 PRIOR WORKS 28 3.3 PROPOSED AREA- AND POWER-EFFICIENT 10B6Q PAM-4 CODER 30 3.4 DESIGN OF THE 10B6Q CODE 33 3.4.1 PAM-4 DC BALANCE 35 3.4.2 PAM-4 TRANSITION DENSITY 35 3.4.3 10B6Q DECODER 37 3.5 IMPLEMENTATION AND MEASUREMENT RESULTS 40 CHAPTER 4 PAM-4 TRANSMITTER AND ADAPTIVE RECEIVER WITH FIXED DATA AND THRESHOLD LEVELS 45 4.1 INTRODUCTION 45 4.2 PRIOR WORKS 47 4.3 ARCHITECTURE AND IMPLEMENTATION 49 4.2.1 PAM-4 TRANSMITTER 49 4.2.2 PAM-4 ADAPTIVE RECEIVER 52 4.3 MEASUREMENT RESULTS 62 CHAPTER 5 ASYMMETRIC SIMULTANEOUS BIDIRECTIONAL TRANSCEIVERS USING WIDE LINEAR RANGE HYBRID 68 5.1 INTRODUCTION 68 5.2 PRIOR WORKS 70 5.3 WIDE LINEAR RANGE (WLR) HYBRID 75 5.3 IMPLEMENTATION 78 5.3.1 SERIALIZER (SER) DESIGN 78 5.3.2 DESERIALIZER (DES) DESIGN 79 5.4 HALF CIRCUIT ANALYSIS OF WLR HYBRID AND LRE 82 5.5 MEASUREMENT RESULTS 88 CHAPTER 6 CONCLUSION 97 BIBLIOGRAPHY 99 ์ดˆ ๋ก 106๋ฐ•

    Adaptation algorithms for data echo cancellation using nonquadratic cost functions

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    Adaptation algorithms for data echo cancellation using nonquadratic cost function

    Estimation and detection of transmission line characteristics in the copper access network

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    The copper access-network operators face the challenge of developing and maintaining cost-effective digital subscriber line (DSL) services that are competitive to other broadband access technologies. The way forward is dictated by the demand of ever increasing data rates on the twisted-pair copper lines. To meet this demand, a relocation of the DSL transceivers in cabinets closer to the customers are often necessary combined with a joint expansion of the accompanying optical-fiber backhaul network. The equipment of the next generation copper network are therefore becoming more scattered and geographically distributed, which increases the requirements of automated line qualification with fault detection and localization. This scenario is addressed in the first five papers of this dissertation where the focus is on estimation and detection of transmission line characteristics in the copper access network. The developed methods apply model-based optimization with an emphasis on using low-order modeling and a priori information of the given problem. More specifically, in Paper I a low-order and causal cable model is derived based on the Hilbert transform. This model is successfully applied in three contributions of this dissertation. In Paper II, a class of low-complexity unbiased estimators for the frequency-dependent characteristic impedance is presented that uses one-port measurements only. The so obtained characteristic impedance paves the way for enhanced time domain reflectometry (a.k.a. TDR) on twisted-pair lines. In Paper III, the problem of estimating a nonhomogeneous and dispersive transmission line is investigated and a space-frequency optimization approach is developed for the DSL application. The accompanying analysis shows which parameters are of interest to estimate and further suggests the introduction of the concept capacitive length that overcomes the necessity of a priori knowledge of the physical line length. In Paper IV, two methods are developed for detection and localization of load coils present in so-called loaded lines. In Paper V, line topology identification is addressed with varying degree of a priori information. In doing so, a model-based optimization approach is employed that utilizes multi-objective evolutionary computation based on one/two-port measurements. A complement to transceiver relocation that potentially enhances the total data throughput in the copper access network is dynamic spectrum management (DSM). This promising multi-user transmission technique aims at maximizing the transmission rates, and/or minimizing the power consumption, by mitigating or cancelling the dominating crosstalk interference between twisted-pair lines in the same cable binder. Hence the spectral utilization is improved by optimizing the transmit signals in order to minimize the crosstalk interference. However, such techniques rely on accurate information of the (usually) unknown crosstalk channels. This issue is the main focus of Paper VI and VII of this dissertation in which Paper VI deals with estimation of the crosstalk channels between twisted-pair lines. More specifically, an unbiased estimator for the square-magnitude of the crosstalk channels is derived from which a practical procedure is developed that can be implemented with standardized DSL modems already installed in the copper access network. In Paper VII the impact such a non-ideal estimator has on the performance of DSM is analyzed and simulated. Finally, in Paper VIII a novel echo cancellation algorithm for DMT-based DSL modems is presented

    Resource-constrained optimal scheduling of SDF graphs via timed automata (extended version)

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    Synchronous dataflow (SDF) graphs are a widely used formalism for modelling, analysing and realising streaming applications, both on a single processor and in a multiprocessing context. Efficient schedules are essential to obtain maximal throughput under the constraint of available number of resources. This paper presents an approach to schedule SDF graphs using a proven formalism of timed automata (TA). TA maintain a good balance between expressiveness and tractability, and are supported by powerful verification tools, e.g. Uppaal. We describe a compositional translation of SDF graphs to TA, and analysis and verification in the Uppaal state-of-the-art tool. This approach does not require any transformation of SDF graphs and helps to find schedules with a compromise between the number of processors required and the throughput. It also allows quantitative model checking and verification of user-defined properties such as the absence of deadlocks, safety, liveness and throughput analysis. This translation also forms the basis for future work to extend this analysis of SDF graphs with new features such as stochastics, energy consumption and costs

    Full-duplex wireless communications: challenges, solutions and future research directions

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    The family of conventional half-duplex (HD) wireless systems relied on transmitting and receiving in different time-slots or frequency sub-bands. Hence the wireless research community aspires to conceive full-duplex (FD) operation for supporting concurrent transmission and reception in a single time/frequency channel, which would improve the attainable spectral efficiency by a factor of two. The main challenge encountered in implementing an FD wireless device is the large power difference between the self-interference (SI) imposed by the deviceโ€™s own transmissions and the signal of interest received from a remote source. In this survey, we present a comprehensive list of the potential FD techniques and highlight their pros and cons. We classify the SI cancellation techniques into three categories, namely passive suppression, analog cancellation and digital cancellation, with the advantages and disadvantages of each technique compared. Specifically, we analyse the main impairments (e.g. phase noise, power amplifier nonlinearity as well as in-phase and quadrature-phase (I/Q) imbalance, etc.) that degrading the SI cancellation. We then discuss the FD based Media Access Control (MAC)-layer protocol design for the sake of addressing some of the critical issues, such as the problem of hidden terminals, the resultant end-to-end delay and the high packet loss ratio (PLR) due to network congestion. After elaborating on a variety of physical/MAC-layer techniques, we discuss potential solutions conceived for meeting the challenges imposed by the aforementioned techniques. Furthermore, we also discuss a range of critical issues related to the implementation, performance enhancement and optimization of FD systems, including important topics such as hybrid FD/HD scheme, optimal relay selection and optimal power allocation, etc. Finally, a variety of new directions and open problems associated with FD technology are pointed out. Our hope is that this treatise will stimulate future research efforts in the emerging field of FD communication

    Orthogonal transmultiplexers : extensions to digital subscriber line (DSL) communications

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    An orthogonal transmultiplexer which unifies multirate filter bank theory and communications theory is investigated in this dissertation. Various extensions of the orthogonal transmultiplexer techniques have been made for digital subscriber line communication applications. It is shown that the theoretical performance bounds of single carrier modulation based transceivers and multicarrier modulation based transceivers are the same under the same operational conditions. Single carrier based transceiver systems such as Quadrature Amplitude Modulation (QAM) and Carrierless Amplitude and Phase (CAP) modulation scheme, multicarrier based transceiver systems such as Orthogonal Frequency Division Multiplexing (OFDM) or Discrete Multi Tone (DMT) and Discrete Subband (Wavelet) Multicarrier based transceiver (DSBMT) techniques are considered in this investigation. The performance of DMT and DSBMT based transceiver systems for a narrow band interference and their robustness are also investigated. It is shown that the performance of a DMT based transceiver system is quite sensitive to the location and strength of a single tone (narrow band) interference. The performance sensitivity is highlighted in this work. It is shown that an adaptive interference exciser can alleviate the sensitivity problem of a DMT based system. The improved spectral properties of DSBMT technique reduces the performance sensitivity for variations of a narrow band interference. It is shown that DSBMT technique outperforms DMT and has a more robust performance than the latter. The superior performance robustness is shown in this work. Optimal orthogonal basis design using cosine modulated multirate filter bank is discussed. An adaptive linear combiner at the output of analysis filter bank is implemented to eliminate the intersymbol and interchannel interferences. It is shown that DSBMT is the most suitable technique for a narrow band interference environment. A blind channel identification and optimal MMSE based equalizer employing a nonmaximally decimated filter bank precoder / postequalizer structure is proposed. The performance of blind channel identification scheme is shown not to be sensitive to the characteristics of unknown channel. The performance of the proposed optimal MMSE based equalizer is shown to be superior to the zero-forcing equalizer

    Efficient Algorithms for Immersive Audio Rendering Enhancement

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    Il rendering audio immersivo รจ il processo di creazione di unโ€™esperienza sonora coinvolgente e realistica nello spazio 3D. Nei sistemi audio immersivi, le funzioni di trasferimento relative alla testa (head-related transfer functions, HRTFs) vengono utilizzate per la sintesi binaurale in cuffia poichรฉ esprimono il modo in cui gli esseri umani localizzano una sorgente sonora. Possono essere introdotti algoritmi di interpolazione delle HRTF per ridurre il numero di punti di misura e per creare un movimento del suono affidabile. La riproduzione binaurale puรฒ essere eseguita anche dagli altoparlanti. Tuttavia, il coinvolgimento di due o piรน gli altoparlanti causa il problema del crosstalk. In questo caso, algoritmi di cancellazione del crosstalk (CTC) sono necessari per eliminare i segnali di interferenza indesiderati. In questa tesi, partendo da un'analisi comparativa di metodi di misura delle HRTF, viene proposto un sistema di rendering binaurale basato sull'interpolazione delle HRTF per applicazioni in tempo reale. Il metodo proposto mostra buone prestazioni rispetto a una tecnica di riferimento. L'algoritmo di interpolazione รจ anche applicato al rendering audio immersivo tramite altoparlanti, aggiungendo un algoritmo di cancellazione del crosstalk fisso, che considera l'ascoltatore in una posizione fissa. Inoltre, un sistema di cancellazione crosstalk adattivo, che include il tracciamento della testa dell'ascoltatore, รจ analizzato e implementato in tempo reale. Il CTC adattivo implementa una struttura in sottobande e risultati sperimentali dimostrano che un maggiore numero di bande migliora le prestazioni in termini di errore totale e tasso di convergenza. Il sistema di riproduzione e le caratteristiche dell'ambiente di ascolto possono influenzare le prestazioni a causa della loro risposta in frequenza non ideale. L'equalizzazione viene utilizzata per livellare le varie parti dello spettro di frequenze che compongono un segnale audio al fine di ottenere le caratteristiche sonore desiderate. L'equalizzazione puรฒ essere manuale, come nel caso dell'equalizzazione grafica, dove il guadagno di ogni banda di frequenza puรฒ essere modificato dall'utente, o automatica, la curva di equalizzazione รจ calcolata automaticamente dopo la misurazione della risposta impulsiva della stanza. L'equalizzazione della risposta ambientale puรฒ essere applicata anche ai sistemi multicanale, che utilizzano due o piรน altoparlanti e la zona di equalizzazione puรฒ essere ampliata misurando le risposte impulsive in diversi punti della zona di ascolto. In questa tesi, GEQ efficienti e un sistema adattativo di equalizzazione d'ambiente. In particolare, sono proposti e approfonditi tre equalizzatori grafici a basso costo computazionale e a fase lineare e quasi lineare. Gli esperimenti confermano l'efficacia degli equalizzatori proposti in termini di accuratezza, complessitร  computazionale e latenza. Successivamente, una struttura adattativa in sottobande รจ introdotta per lo sviluppo di un sistema di equalizzazione d'ambiente multicanale. I risultati sperimentali verificano l'efficienza dell'approccio in sottobande rispetto al caso a banda singola. Infine, viene presentata una rete crossover a fase lineare per sistemi multicanale, mostrando ottimi risultati in termini di risposta in ampiezza, bande di transizione, risposta polare e risposta in fase. I sistemi di controllo attivo del rumore (ANC) possono essere progettati per ridurre gli effetti dell'inquinamento acustico e possono essere utilizzati contemporaneamente a un sistema audio immersivo. L'ANC funziona creando un'onda sonora in opposizione di fase rispetto all'onda sonora in arrivo. Il livello sonoro complessivo viene cosรฌ ridotto grazie all'interferenza distruttiva. Infine, questa tesi presenta un sistema ANC utilizzato per la riduzione del rumore. Lโ€™approccio proposto implementa una stima online del percorso secondario e si basa su filtri adattativi in sottobande applicati alla stima del percorso primario che mirano a migliorare le prestazioni dellโ€™intero sistema. La struttura proposta garantisce un tasso di convergenza migliore rispetto all'algoritmo di riferimento.Immersive audio rendering is the process of creating an engaging and realistic sound experience in 3D space. In immersive audio systems, the head-related transfer functions (HRTFs) are used for binaural synthesis over headphones since they express how humans localize a sound source. HRTF interpolation algorithms can be introduced for reducing the number of measurement points and creating a reliable sound movement. Binaural reproduction can be also performed by loudspeakers. However, the involvement of two or more loudspeakers causes the problem of crosstalk. In this case, crosstalk cancellation (CTC) algorithms are needed to delete unwanted interference signals. In this thesis, starting from a comparative analysis of HRTF measurement techniques, a binaural rendering system based on HRTF interpolation is proposed and evaluated for real-time applications. The proposed method shows good performance in comparison with a reference technique. The interpolation algorithm is also applied for immersive audio rendering over loudspeakers, by adding a fixed crosstalk cancellation algorithm, which assumes that the listener is in a fixed position. In addition, an adaptive crosstalk cancellation system, which includes the tracking of the listener's head, is analyzed and a real-time implementation is presented. The adaptive CTC implements a subband structure and experimental results prove that a higher number of bands improves the performance in terms of total error and convergence rate. The reproduction system and the characteristics of the listening room may affect the performance due to their non-ideal frequency response. Audio equalization is used to adjust the balance of different audio frequencies in order to achieve desired sound characteristics. The equalization can be manual, such as in the case of graphic equalization, where the gain of each frequency band can be modified by the user, or automatic, where the equalization curve is automatically calculated after the room impulse response measurement. The room response equalization can be also applied to multichannel systems, which employ two or more loudspeakers, and the equalization zone can be enlarged by measuring the impulse responses in different points of the listening zone. In this thesis, efficient graphic equalizers (GEQs), and an adaptive room response equalization system are presented. In particular, three low-complexity linear- and quasi-linear-phase graphic equalizers are proposed and deeply examined. Experiments confirm the effectiveness of the proposed GEQs in terms of accuracy, computational complexity, and latency. Successively, a subband adaptive structure is introduced for the development of a multichannel and multiple positions room response equalizer. Experimental results verify the effectiveness of the subband approach in comparison with the single-band case. Finally, a linear-phase crossover network is presented for multichannel systems, showing great results in terms of magnitude flatness, cutoff rates, polar diagram, and phase response. Active noise control (ANC) systems can be designed to reduce the effects of noise pollution and can be used simultaneously with an immersive audio system. The ANC works by creating a sound wave that has an opposite phase with respect to the sound wave of the unwanted noise. The additional sound wave creates destructive interference, which reduces the overall sound level. Finally, this thesis presents an ANC system used for noise reduction. The proposed approach implements an online secondary path estimation and is based on cross-update adaptive filters applied to the primary path estimation that aim at improving the performance of the whole system. The proposed structure allows for a better convergence rate in comparison with a reference algorithm

    FFT and FIR Filter implementations for the DSL MODEMS

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    Broad band digital communication that operates over a standard copper wires. It requires the DSL modems which splits the transmissions into 2 frequency bands. The lower frequencies for voice and the higher frequencies for digital data (internet) in order to transmit the data to larger distances through a copper cable we need modulation techniques. Generally in this DSL modems modulation used is QAM technique. The output of the QAM is complex data this complex data we cannot transfer directly through a copper cable because the data should be in time domain or otherwise the phase of the data which is in frequency domain can be lost, in copper cable so this data should be converted in time domain by using IDFT technique. As IDFT requires more number of complex multiplications and more number of complex additions in comparison to IFFT so to reduce the additions and multiplications IFFT technique is used. At the receiver side we can retrieve the same data by using FFT technique. In this section the implemented FFT architecture is fully efficient and this architecture will require less area. And before we have to transmit through the copper line we have to do interpolation or decimation by using the Filtering operation. The implemented poly phase architecture for the filtering is fully efficient, symmetrical and it requires less number of multipliers

    Channelized voice over digital subscriber line

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    The objective of this article is to present a promising voice over digital subscriber line (VoDSL) solution: an alternative method that uses physical layer transportation to provide channelized VoDSL (CVoDSL). This article also presents the advantages that the CVoDSL provides to the customers in terms of high-quality services and lower cost, and service providers in terms of market growth and success. It also offers a set of requirements, architectural design, and implementation scenarios that provide end-to-end solutions for CVoDSL
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