Electrical Communication Engineering (ECE)
https://etd.iisc.ac.in/handle/2005/18
Sun, 29 Jan 2023 16:58:17 GMT2023-01-29T16:58:17ZElectrical Communication Engineering (ECE)https://etd.iisc.ac.in:443/bitstream/id/4fc045e0-affb-44c4-a89f-50045c7c7a0a/
https://etd.iisc.ac.in/handle/2005/18
0.5V Subthreshold Region Operated Ultra Low Power Passive Sigma Delta ADC in 180 NM CMOS Technology
https://etd.iisc.ac.in/handle/2005/4318
0.5V Subthreshold Region Operated Ultra Low Power Passive Sigma Delta ADC in 180 NM CMOS Technology
Satyadev, Singh Kamlesh
With increasing demand of IoT devices, medical devices, remote sensors; the design of low power analog interface is becoming focus. Generally, for low frequency applications the Sigma Delta ADCs are used due to their very good resolution capability for such interfaces. Hence extensive work is being done to design ultra-low power Sigma Delta ADC. Most of the work has been done on optimizing loop filter design both in terms of architecture and its basic building element, op-amps. Recently, one of the prime focus of such research is Passive Sigma Delta ADC, where the loop filter is implemented with passive elements instead of active elements like op-amp.
In this work, a subthreshold region operated Passive Sigma Delta design has been explored. The thesis discusses a different analytical approach to analyze passive SDM ADC than the usual circuit level analysis used traditionally. The Simulink modeling of a passive SDM ADC was addressed to study block level performance. The circuit level implementation was carried out in Cadence environment. Both pre-and-post layout level simulations were conducted.
The passive SDM ADC designed in this work has a Sampling frequency of 10MHz, with a signal BW of 10KHz. An ENOB of 10.4 bits is achieved at power dissipation of only 4μW. The proposed ADC has very competitive FOM (Figure of Merit) in comparison with published literature.
https://etd.iisc.ac.in/handle/2005/4318Achieving The Optimal Diversity-Multiplexing Gain Tradeoff For MIMO Channels With And Without Feedback
https://etd.iisc.ac.in/handle/2005/1410
Achieving The Optimal Diversity-Multiplexing Gain Tradeoff For MIMO Channels With And Without Feedback
Pawar, Sameer A
Fri, 09 Sep 2011 00:00:00 GMThttps://etd.iisc.ac.in/handle/2005/14102011-09-09T00:00:00ZAdaptive Joint Source/Channel Rate Allocation Policies For Delay Sensitive Applications Over Fading Channels
https://etd.iisc.ac.in/handle/2005/1192
Adaptive Joint Source/Channel Rate Allocation Policies For Delay Sensitive Applications Over Fading Channels
Thejaswi, Chandrashekhara P S
Fri, 13 May 2011 00:00:00 GMThttps://etd.iisc.ac.in/handle/2005/11922011-05-13T00:00:00ZAdjacent Independent Row (Air) Matrices and Index Coding
https://etd.iisc.ac.in/handle/2005/5406
Adjacent Independent Row (Air) Matrices and Index Coding
Mahesh Babu, Vaddi
An index coding problem, comprises a transmitter that has a set of independent
messages and a set of receivers. Each receiver knows a subset of messages, called
its side-information, and demands another subset of messages, called its want-set.
The transmitter can take cognizance of the side-information of the receivers and
broadcast coded messages, called the index code, over a noiseless channel. The
objective is to minimize the number of coded transmissions, called the length of the
index code, such that each receiver can decode its wanted messages using its sideinformation
and the coded messages. An index coding problem is single unicast if
the want-sets of the receivers are disjoint and the cardinality of want-set of every
receiver is one. In a single unicast index coding problem, we have equal number of
messages and receivers. A single unicast index coding problem is called symmetric
if the side-information of the receivers is symmetric with respect to their wanted
message. Motivated with topological interference management problems, Maleki,
Cadambe and Jafar studied the symmetric index coding problems. This thesis
deals with the symmetric index coding problems and present some interesting
results.
In this work, we construct binary matrices of size m × n such that any n
adjacent rows of the matrix are linearly independent over every finite field for any
arbitrary positive integers m and n (m ≥ n). We call these matrices as Adjacency
Independent Row (AIR) matrices. We derive combinatorial properties of AIR
matrices.
We use AIR matrices to construct optimal or near-optimal index codes for various
symmetric settings. By using the combinatorial properties of AIR matrices,
we give a simple low-complexity decoding procedure for the constructed optimal
or near-optimal index codes. By using this decoding procedure, we give a reduced set of side-information required by each receiver to decode its wanted message. We
also derive bounds on the broadcast rate of two well known classes of symmetric
settings and derive the capacity for some special cases of the same.
The interlinked cycle (IC) structure, that generalizes cycles and cliques was
defined by Thapa, Ong and Johnson. Interlinked-cycle-cover (ICC) scheme that
leverages IC structures as side-information graphs to construct scalar linear index
codes was proposed. A class of infinitely many digraphs, where the proposed
scalar linear codes based on ICC scheme are optimal were characterized. Thapa
et. al. conjectured that for any IC structure, the ICC scheme is optimal. It was
also conjectured that for any digraph, the ICC scheme performs at least as well as
the partial-clique-cover scheme. In this work, we disprove both the conjectures.
We provide an addition to the class of IC structures by providing optimal length
index codes for IC structures with one cycle among non-inner vertex set.
https://etd.iisc.ac.in/handle/2005/5406