Centre of Excellence in Wireless Technology

Center of Excellence in Wireless Technology

Baskaran Dhivagar

Kiran Kumar Kuchi

Bhaskar Ramamurthi

Krishnamurthi Giridhar

Padmanabhan Madampu Suryasarman

Dileep Manisseri Kalathil

Vinod Ramaswamy

Deviraj Klutto Milleth Jeniston

Jeniston Deviraj Klutto Milleth

Prasanth Karunakaran

Yerrapareddy Sivakishore Reddy

Geordie George

Embodiments disclosed herein reduce interference at pilot symbols and also enable good interference measurements by using a combination pilot tones and null tones along with null tones. In this type of system, the receivers estimate the channel state information without any strong interference from the neighboring transmitters, and at the same time it can also measure either the individual interference channel states or the interference covariances from the silent periods. It uses these measurements thus obtained to calculate the post processing SINR, and then compute and report the wideband and subband CQIs to the transmitter. The groups of transmitters are reused in geographically separated region using a frequency reuse structure. In a preferred implementation, pilot signal is precoded using a multi-antenna precoder. The precoder may be same for pilot and data.

Pilot aided data transmission and reception with interference mitigation in wireless systems

Precoding for multiple transmission streams in multiple antenna systems. Disclosed herein is a general method that transmits signal from multiple antennas using a one/two dimensional precoder. This precoder is fixed in a given resource block (RB) or slot, which is composed of P subcarriers and Q OFDM symbols (where the values for P and Q are greater than or equal to 1). The precoder in each resource block may take same or different values, which span the two dimensional time-frequency grid. The precoder is chosen as a function of either logical frequency index or physical frequency index of the RB.

Precoding for single transmission streams in multiple antenna systems

Embodiments disclosed herein reduce interference at pilot symbols and also enable good interference measurements by using a combination pilot tones and null tones along with null tones. In this type of system, the receivers can estimate tile channel state information without any interference from the remaining transmitters and at the same time the receiver can measure either the individual interference channel states or the interference covariances from the silent periods. The groups of transmitters are reused in geographically separated region using a frequency reuse structure. In a preferred implementation, pilot signal is precoded using a multi-antenna precoder. The precoder may be same for pilot and data.

Embodiments herein provide methods and systems for enhancing interference mitigation using conjugate symbol repetition and phase randomization on a set of subcarriers. The repeated data tone in the signal is complex-conjugated before transmission, when the repetition factor is two. When the repetition factor is greater than two, a combination of conjugate repetition and random/deterministic phase variation of the repeated tones is used to mitigate the interference mitigation. Embodiments further disclose Collision Free Interlaced Pilot PRU Structures that can be used with or without conjugate symbol repetition and phase randomization for interference mitigation.

Methods and systems for interference mitigation

Precoding for multiple transmission streams in multiple antenna systems. Embodiments herein disclose a general method that transmits signal from multiple antennas using a one/two dimensional precoder followed by STBC/SFBC or SM encoder. This precoder is fixed in a given resource block (RB) or slot, which is composed of P subcarriers and Q OFDM symbols (where the values for P and Q are greater than or 5 equal to 1). The precoder in each resource block may take same or different values, which span the two dimensional time-frequency grid. The precoder is chosen as a function of either logical frequency index or physical frequency index of the RB.

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Chennai, India

Baskaran Dhivagar