Noncooperative Cellular Wireless with Unlimited Numbers of Base Station Antennas
TL;DR: A cellular base station serves a multiplicity of single-antenna terminals over the same time-frequency interval and a complete multi-cellular analysis yields a number of mathematically exact conclusions and points to a desirable direction towards which cellular wireless could evolve.
Abstract: A cellular base station serves a multiplicity of single-antenna terminals over the same time-frequency interval. Time-division duplex operation combined with reverse-link pilots enables the base station to estimate the reciprocal forward- and reverse-link channels. The conjugate-transpose of the channel estimates are used as a linear precoder and combiner respectively on the forward and reverse links. Propagation, unknown to both terminals and base station, comprises fast fading, log-normal shadow fading, and geometric attenuation. In the limit of an infinite number of antennas a complete multi-cellular analysis, which accounts for inter-cellular interference and the overhead and errors associated with channel-state information, yields a number of mathematically exact conclusions and points to a desirable direction towards which cellular wireless could evolve. In particular the effects of uncorrelated noise and fast fading vanish, throughput and the number of terminals are independent of the size of the cells, spectral efficiency is independent of bandwidth, and the required transmitted energy per bit vanishes. The only remaining impairment is inter-cellular interference caused by re-use of the pilot sequences in other cells (pilot contamination) which does not vanish with unlimited number of antennas.
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AT&T1
TL;DR: In this paper, an apparatus including a waveguide, an antenna, and a transmitter can be used to facilitate propagation of the first electromagnetic waves at least in part on a surface of the waveguide.
Abstract: Aspects of the subject disclosure may include, for example, an apparatus including a waveguide, an antenna, and a transmitter. The transmitter can facilitate transmission of first electromagnetic waves via the antenna, the first electromagnetic waves having a fundamental mode. The waveguide can facilitate propagation of the first electromagnetic waves at least in part on a surface of the waveguide. The waveguide can be positioned at a location that enables the first electromagnetic waves to induce second electromagnetic waves having fundamental and non-fundamental modes that propagate on a surface of a transmission medium. Other embodiments are disclosed.
282 citations
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AT&T1
TL;DR: In this paper, a waveguide system for determining an event associated with a mode of transmitting or receiving electromagnetic waves on a surface of a transmission medium, identifying according to the event an updated mode for transmission or receiving adjusted electromagnetic wave on the surface of the transmission medium.
Abstract: Aspects of the subject disclosure may include, for example, a waveguide system for determining an event associated with a mode of transmitting or receiving electromagnetic waves on a surface of a transmission medium, identifying according to the event an updated mode for transmitting or receiving adjusted electromagnetic waves on the surface of a transmission medium, and transmitting or receiving the adjusted electromagnetic waves based on the updated mode. Other embodiments are disclosed.
282 citations
Patent•
AT&T1
TL;DR: In this article, a node device includes an interface configured to receive first signals, and a plurality of coupling devices are configured to launch the first signals on a transmission medium, at corresponding plurality of non-optical carrier frequencies, wherein the plurality of first guided electromagnetic waves are bound to a physical structure of the transmission medium.
Abstract: Aspects of the subject disclosure may include, for example, a node device includes an interface configured to receive first signals. A plurality of coupling devices are configured to launch the first signals on a transmission medium as a plurality of first guided electromagnetic waves at corresponding plurality of non-optical carrier frequencies, wherein the plurality of first guided electromagnetic waves are bound to a physical structure of the transmission medium. Other embodiments are disclosed.
282 citations
Patent•
AT&T1
TL;DR: In this article, a coupler including a receiving portion that receives a first electromagnetic wave conveying first data from a transmitting device is described, where a guiding portion guides the first wave to a junction for coupling the wave to the transmission medium and the coupling of the wave propagates via at least one first guided wave mode.
Abstract: Aspects of the subject disclosure may include, for example, a coupler including a receiving portion that receives a first electromagnetic wave conveying first data from a transmitting device. A guiding portion guides the first electromagnetic wave to a junction for coupling the first electromagnetic wave to a transmission medium. The first electromagnetic wave propagates via at least one first guided wave mode. The coupling of the first electromagnetic wave to the transmission medium forms a second electromagnetic wave that is guided to propagate along the outer surface of the transmission medium via at least one second guided wave mode that differs from the at least one first guided wave mode. Other embodiments are disclosed.
281 citations
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AT&T1
TL;DR: In this paper, a system for receiving telemetry information from an apparatus that induces electromagnetic waves on a wire surface of a wire of a power grid for delivery of communication signals to a recipient communication device coupled to the power grid is described.
Abstract: Aspects of the subject disclosure may include, for example, a system for receiving telemetry information from an apparatus that induces electromagnetic waves on a wire surface of a wire of a power grid for delivery of communication signals to a recipient communication device coupled to the power grid, and detecting a condition from the telemetry information that is adverse to a delivery of the communication signals to the recipient communication device. Other embodiments are disclosed.
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References
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TL;DR: This paper addresses digital communication in a Rayleigh fading environment when the channel characteristic is unknown at the transmitter but is known (tracked) at the receiver with the aim of leveraging the already highly developed 1-D codec technology.
Abstract: This paper addresses digital communication in a Rayleigh fading environment when the channel characteristic is unknown at the transmitter but is known (tracked) at the receiver. Inventing a codec architecture that can realize a significant portion of the great capacity promised by information theory is essential to a standout long-term position in highly competitive arenas like fixed and indoor wireless. Use (n T , n R ) to express the number of antenna elements at the transmitter and receiver. An (n, n) analysis shows that despite the n received waves interfering randomly, capacity grows linearly with n and is enormous. With n = 8 at 1% outage and 21-dB average SNR at each receiving element, 42 b/s/Hz is achieved. The capacity is more than 40 times that of a (1, 1) system at the same total radiated transmitter power and bandwidth. Moreover, in some applications, n could be much larger than 8. In striving for significant fractions of such huge capacities, the question arises: Can one construct an (n, n) system whose capacity scales linearly with n, using as building blocks n separately coded one-dimensional (1-D) subsystems of equal capacity? With the aim of leveraging the already highly developed 1-D codec technology, this paper reports just such an invention. In this new architecture, signals are layered in space and time as suggested by a tight capacity bound.
6,812 citations
"Noncooperative Cellular Wireless wi..." refers background in this paper
...A point-to-point MIMO system [2] requires expensive multiple-antenna terminals....
[...]
TL;DR: Under certain mild conditions, this scheme is found to be throughput-wise asymptotically optimal for both high and low signal-to-noise ratio (SNR), and some numerical results are provided for the ergodic throughput of the simplified zero-forcing scheme in independent Rayleigh fading.
Abstract: A Gaussian broadcast channel (GBC) with r single-antenna receivers and t antennas at the transmitter is considered. Both transmitter and receivers have perfect knowledge of the channel. Despite its apparent simplicity, this model is, in general, a nondegraded broadcast channel (BC), for which the capacity region is not fully known. For the two-user case, we find a special case of Marton's (1979) region that achieves optimal sum-rate (throughput). In brief, the transmitter decomposes the channel into two interference channels, where interference is caused by the other user signal. Users are successively encoded, such that encoding of the second user is based on the noncausal knowledge of the interference caused by the first user. The crosstalk parameters are optimized such that the overall throughput is maximum and, surprisingly, this is shown to be optimal over all possible strategies (not only with respect to Marton's achievable region). For the case of r>2 users, we find a somewhat simpler choice of Marton's region based on ordering and successively encoding the users. For each user i in the given ordering, the interference caused by users j>i is eliminated by zero forcing at the transmitter, while interference caused by users j
2,616 citations
"Noncooperative Cellular Wireless wi..." refers background in this paper
...An alternative to a point-to-point MIMO system is a multiuser MIMO system [3], [4], [5], [6] in which an antenna array simultaneously serves a multiplicity of autonomous terminals....
[...]
Book•
28 Jun 2004TL;DR: A tutorial on random matrices is provided which provides an overview of the theory and brings together in one source the most significant results recently obtained.
Abstract: Random matrix theory has found many applications in physics, statistics and engineering since its inception. Although early developments were motivated by practical experimental problems, random matrices are now used in fields as diverse as Riemann hypothesis, stochastic differential equations, condensed matter physics, statistical physics, chaotic systems, numerical linear algebra, neural networks, multivariate statistics, information theory, signal processing and small-world networks. This article provides a tutorial on random matrices which provides an overview of the theory and brings together in one source the most significant results recently obtained. Furthermore, the application of random matrix theory to the fundamental limits of wireless communication channels is described in depth.
2,308 citations
"Noncooperative Cellular Wireless wi..." refers background in this paper
...It can be shown that the vector φkjΦ ∗ l has exactly the same probability distribution as does any row vector of Φl [15], [16]....
[...]
01 Jan 2004
2,180 citations
TL;DR: It is shown that the dirty paper achievable region achieves the sum-rate capacity of the MIMO BC by establishing that the maximum sum rate of this region equals an upper bound on the sum rate.
Abstract: We consider a multiuser multiple-input multiple- output (MIMO) Gaussian broadcast channel (BC), where the transmitter and receivers have multiple antennas. Since the MIMO BC is in general a nondegraded BC, its capacity region remains an unsolved problem. We establish a duality between what is termed the "dirty paper" achievable region (the Caire-Shamai (see Proc. IEEE Int. Symp. Information Theory, Washington, DC, June 2001, p.322) achievable region) for the MIMO BC and the capacity region of the MIMO multiple-access channel (MAC), which is easy to compute. Using this duality, we greatly reduce the computational complexity required for obtaining the dirty paper achievable region for the MIMO BC. We also show that the dirty paper achievable region achieves the sum-rate capacity of the MIMO BC by establishing that the maximum sum rate of this region equals an upper bound on the sum rate of the MIMO BC.
1,802 citations
"Noncooperative Cellular Wireless wi..." refers background in this paper
...An alternative to a point-to-point MIMO system is a multiuser MIMO system [3], [4], [5], [6] in which an antenna array simultaneously serves a multiplicity of autonomous terminals....
[...]