Cost-Efficient, High-Volume Transmission: Advanced Transmission Design and Architecture of Next Generation RF Modems and Front-Ends

Electrical Balance Duplexer Field Trials in High-Speed Rail Scenarios

“…This data is then incorporated in to an EBD circuit simulation to provide a highly realistic model of the variable antenna reflection coefficient. The simulation assumes a symmetrical, lossless hybrid junction, and ideal continuously variable lumped element components in the tunable balancing impedance circuit, and calculates the mean Tx-Rx isolation across a 20 MHz band as a function of time 2 . This EBD circuit simulation is identical to the simulations presented previously in [10]- [12], allowing for direct comparison of results.…”

“…State of the art tunable filters cannot meet the demanding requirements for steep roll-off and low insertion loss [1]; supporting multi-band operation therefore requires multiple separate fixed frequency duplexers and switches for band selection [2]. Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) currently defines 30 FDD bands [3], however supporting all of these bands with the current architecture is both technically infeasible and commercially unviable, as the resulting circuit would be prohibitively large, lossy, and expensive.…”

“…roaming on LTE [2]. Producing a tunable RF front-end is a key challenge for the next generation of mobile devices.…”

Tunable Frequency-Division Duplex RF Front End Using Electrical Balance and Active Cancellation

“…Supporting multiband operation requires multiple offchip duplexers, which prohibits covering more than several bands. Because of this, mobile devices currently support only a region specific subset of the >30 FDD bands defined in the 3GPP standards, preventing global roaming on 3GPP long term evolution (LTE), and motivating research into alternative duplexing technologies [1]. In recent years substantial progress has been made toward a fully tunable and reconfigurable radio frequency (RF) frontend [1], [2], but tunable filters which can provide the low insertion loss (IL) and steep roll-off required for FDD remain a distant prospect [3].…”

Dynamic Performance of Electrical Balance Duplexing in a Vehicular Scenario

“…surface acoustic wave (SAW) filters), which effectively limit the number of bands that can be covered due to the cost, size, and loss associated with these components [6], [7]. EBDs implement a form of self-interference cancellation, and are also of interest as the first stage of cancellation in in-band full-duplex (IBFD) transceivers [3], [8].…”