504 different physical-layer cell ids are composed of 168 different physical-layer cell id groups each of 3 physical layer ids within the group There are – primary synchronization signal – based on a frequency domain Zadoff-Chu sequence indicating the physical layer id, – secondary synchronization signal indicating the physical layer cell id group. The mapping … Read more
For channel estimation different types of reference signals are in use: – Cell specific reference signals. – MBSFN reference signals. – UE specific reference signals CELL-SPECIFIC REFERENCE SIGNALS These signals are transmitted for all non-MBSFN subframes only where subcarrier spacing is 15 kHz. In MBSFN subframes only the first 2 OFDM symbols can be used. … Read more
Mobile WiMAX allows any telecommunications to go mobile. Mobile WiMAX takes the fixed wireless application a step furher and enables cell phone-like applications on a much larger scale. For example, mobile WiMAX enables streaming video to be broadcast from a speeding police or other emergency vehicle at over 70 MPH. It potentially replaces cell phones … Read more
Second-generation broadband wireless systems were able to overcome the LOS issue and to provide more capacity. This was done through the use of a cellular architecture and implementation of advanced-signal processing techniques to improve the link and system performance under multipath conditions. Several start-up companies developed advanced proprietary solutions that provided significant performance gains over … Read more
Multi-path combination in the BSC during soft handoffMulti-path combination in the BTS during softer handoffs Soft handoff means that during the handoff of a mobile station at the coverage edge areas of two or multiple base stations, the mobile station receives the signals from multiple base stations (two in most cases) at the same … Read more
Two points are important here: Maximum number of shift register (N) Mask The period of out put sequence is 2N-1 bits Only sequence offset is change when the mask is changed PN stands for Pseudorandom Noise sequence In CDMA system, user information is encrypted by means of scrambling. The scramble code used here is … Read more
The Tx Div can be applied on all the physical channels: Physical DL Shared Channel (PDSCH) Physical Broadcast Channel (PBCH) Physical Control Format Indicator Channel (PCFICH) Physical Downlink Control Channel (PDCCH) The other MIMO schemes are only applicable to the PDSCH Like the MIMO required a UE-specific feedback (RI and PMI), it is not possible … Read more
MIMO-MU = Multi user It is used only in Uplink. MIMO-MU does not increase the individual user’s data rate but it does offer cell capacity gains that are similar to, or better than, those provided by MIMO-SU. The UE does not require the expense and power drain of two transmitters, yet the cell still benefits … Read more
India’s telecoms regulator has ordered two mobile networks, Etisalat DB and STel to restart their mothballed networks within three days. The two companies lost their licenses when the Supreme Court cancelled the 2008 GSM license allocation, and announced that they would close their services as a result. However, the TRAI has told them to keep … Read more
The American Civil Liberties Union this weekend released the results of public records requests filed last August to hundreds of local police departments across the country, asking them about their policies, practices, and procedures for tracking cell phone records. As The New York Times reported on Sunday, the records show that the practice of … Read more