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Rosnes E.,Ceragon Networks
IEEE Transactions on Information Theory | Year: 2012

An interleaver is a critical component for the channel coding performance of turbo codes. Algebraic constructions are of particular interest because they admit analytical designs and simple, practical hardware implementations. Also, the recently proposed quadratic permutation polynomial (QPP)-based interleavers by Sun and Takeshita have provided excellent performance for short-to-medium block lengths, and have been selected for the 3GPP LTE standard. In this paper, we derive some upper bounds on the best achievable minimum distance d min of QPP-based conventional binary turbo codes (with tailbiting termination, or dual termination when the interleaver length N is sufficiently large) that are tight for larger block sizes. In particular, we show that the minimum distance is at most 2(2 ν+1+9), independent of the interleaver length, when there exists an inverse polynomial of degree two, where ν is the degree of the primitive feedback and monic feedforward polynomials. However, allowing the QPP to have no inverse polynomials of degree two may give strictly larger minimum distances (and lower multiplicities). In particular, we provide several QPPs with no quadratic inverse for some of the 3GPP LTE interleaver lengths giving a d min with the 3GPP LTE constituent encoders which is strictly larger than 50. For instance, we have found a QPP for N=6016 which gives an estimated d min of 57. Furthermore, we provide the exact minimum distances and the corresponding multiplicities for all 3GPP LTE turbo codes (with dual termination) which shows that the best minimum distance is 51. Finally, we compute the best achievable minimum distances with QPP interleavers for all 3GPP LTE interleaver lengths N = 4096, and compare these minimum distances with the ones we get when using the 3GPP LTE polynomials. © 2012 IEEE.


Patent
Ceragon Networks | Date: 2011-11-16

A method for managing traffic in a communication network which includes a protected path including a first path and a second path, including refraining from sending redundant data along the second path, and using freed up communication capacity obtained by refraining from sending redundant data along the second path for sending other data along the second path. The above-described method and further comprising measuring path integrity, in which the refraining from sending and the using freed up communication capacity depend, at least partly, on meeting a stability criterion applied to the measured path integrity. A network management unit (505, 665, 675) configured to functionally connect to a communication node (605, 655, 680) configured to provide path protection by sending redundant data along a first path (430) and a second path (475), configured to cause the communication node to refrain from sending redundant data along the second path, and use freed up communication capacity, obtained by causing the communication node to refrain from sending redundant data along the second path, for sending other data along the second path. Related apparatus and methods are also described.


Patent
Ceragon Networks | Date: 2013-07-01

A method for a QAM receiver to decide a value of a received symbol of an N-point QAM constellation transmission including extracting coordinate values for the received symbol, and using a decision method for deciding the value of the received symbol based on the extracted coordinate values, in which the decision method for the N-point QAM constellation is updated based on a clustering of received symbols. A method for a QAM transmitter to modify an N-point QAM constellation including starting with an initial N-point QAM constellation, measuring a clustering of coordinates of the N-point QAM constellation, shifting coordinates of at least one symbol of the N-point QAM constellation, and producing a modified constellation with shifted coordinates, wherein the shifting is based on data describing a clustering of at least some symbols of the N-point QAM constellation. Related apparatus and methods are also described.


Patent
Ceragon Networks | Date: 2012-06-13

A method for interference reduction in transmission of at least two single carrier frequency continuous communication beams including producing a first communication signal for a first digital communication link, producing a second communication signal for a second digital communication link, transmitting the first communication signal over a first continuous communication beam at a first frequency, transmitting the second communication signal over a second continuous communication beam at the first frequency, characterized by modifying the first communication signal using transmitter interference cancellation. A method for interference reduction in reception of at least two single carrier frequency continuous communication beams including receiving a first received signal from a first digital communication link, receiving a second received signal from a second digital communication link, modifying the first received signal, adding the modified first received signal to the second received signal, thereby producing a reduced-interference second received signal, characterized by the modifying of the first received signal being based, at least in part, on reducing an error rate of the reduced-interference second received signal. Related apparatus and methods are also described.


Patent
Ceragon Networks | Date: 2011-05-12

A method for managing traffic in a communication network which includes a protected path including a first path and a second path, including refraining from sending redundant data along the second path, and using freed up communication capacity obtained by refraining from sending redundant data along the second path for sending other data along the second path. The above-described method and further comprising measuring path integrity, in which the refraining from sending and the using freed up communication capacity depend, at least partly, on meeting a stability criterion applied to the measured path integrity. A network management unit configured to functionally connect to a communication node configured to provide path protection by sending redundant data along a first path and a second path, configured to cause the communication node to refrain from sending redundant data along the second path, and use freed up communication capacity, obtained by causing the communication node to refrain from sending redundant data along the second path, for sending other data along the second path. Related apparatus and methods are also described.


Patent
Ceragon Networks | Date: 2016-06-13

A method for a network controller to carry out automatic channel allocation for a network of wireless communication links between communication nodes, the method including determining an estimated signal attenuation between communication nodes in a network, allocating wireless channels, determined by a set of transmission parameters, to a plurality of wireless communication links in the network, based, at least in part, on the estimated signal attenuation, sending a message to a first communication node, the message instructing the first communication node to use a set of transmission parameters for communicating a first wireless communication link connecting the first communication node to a second communication node at an opposite end of the first wireless communication link, the transmission parameters based, at least in part, on the allocating wireless channels. Related apparatus and methods are also described.


A method of communicating bi-directionally over a wireless communication system including sending data from a first location, from a first antenna, over a first plurality of signals at different frequencies, to a second plurality of spatially separated antennas at a second location, each of the second plurality of spatially separated antennas feeding a corresponding transmitter/receiver of a plurality of transmitter/receivers at the second location. A method of communicating over a wireless communication system including transmitting same data from a first location, using each one of a plurality of Adaptive Coding and Modulation (ACM) signals at different frequencies, to receivers corresponding to each one of the frequencies at a second location, receiving the transmitted signals, and combining the received signals. Related apparatus and methods are also described.


Patent
Ceragon Networks | Date: 2011-09-27

A method of allocating wireless communication capacity in a wireless point-to-point link including obtaining a channel having a bandwidth for use in the wireless point-to-point link, allocating a first portion of the bandwidth for use for transmitting from a first point to a second point of the wireless point-to-point link, and allocating a second portion of the bandwidth for use for transmitting from the second point to the first point of the wireless point-to-point link, in which the bandwidth is asymmetrically assigned between the first portion and the second portion. Related apparatus and methods are also described.


A method for symbol timing synchronization in multiple-input multiple-output (MIMO) communication, the method including transmitting a first symbol sequence including a preamble symbol sequence S1 from a first transmitting location, transmitting a second symbol sequence from a second transmitting location, the first and second symbol sequences being modulated onto a same carrier frequency, receiving a first mixture of the first and the second symbol sequences at a first receiving location, cross correlating the first mixture with a symbol sequence P1 thereby producing a first correlation output, and determining a first timing offset for receiving the first symbol sequence based, at least in part, on the first correlation output. Related apparatus and methods are also described.


Patent
Ceragon Networks | Date: 2011-03-30

A method for managing protection of a plurality of defmed paths in a communication system including listing the defmed paths, each item in the list including a defmed path identifier, a defined path ingress node, a defined path egress node, and a defmed path protection period, wherein some of the defmed paths share an ingress node and an egress node, managing a sending of Continuity Check Messages (CCMs) along at least some of the defined paths, such that a CCM is sent every protection period, and for at least a plurality of the defined paths which share an ingress node and an egress node, managing a sharing of the protection of the plurality of the defined paths, the sharing including sending one set of CCMs, shared by the plurality of the defined paths, at a frequency based, at least in part, on a shortest one of the protection periods of the plurality of the defined paths. A method for protecting a plurality of paths which share at least one leg in a communication network, including sharing, between the paths, Continuity Check Messages (CCMs) for at least the shared leg. Related apparatus and methods are also described.

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