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Taking 4G and 5G beyond speed: know how Reach Mobile is using this technology for social good

Four billion people worldwide without a basic connection, and many in the US who cannot afford a monthly phone plan. Now, the mobile service you purchase every month can help give meaningful connectivity to someone in need. Reach Mobile is a new mobile service that launched in the US in 2019. Running on the nation's largest and most reliable 4G LTE network, this boutique mobile service offers all the speed and reliability of the "big four" carriers (Verizon, ATT, Sprint, T-Mobile). But reliability and coverage aside, there are a few major differences between Reach and more traditional carriers. Reach Mobile doesn’t have any stores. Instead of visiting a store to manage your phone plan, you simply open an app. In fact, you can sign up for Reach, pick a plan, activate your new service, and monitor anything related to your mobile service, all from the app. Seems anti-social? It's not… just smart. Every Reach Mobile plan helps connect someone in need around the ...
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Positioning Reference Signal PRS LTE

Positioning Reference Signal (PRS) is taken into consideration in one of the LTE release 9 features to determine the location of User Equipment (UE) based on radio access network information. Now you might be thinking that what is the necessity of PRS,  if we have a GPS technology already built in smartphones and in other cellular equipment. Just think of it  J (GPS may not be accurate always and GPS services may not be available all around the geographical areas , also the accuracy of functioning GPS depends on money you have paid for the services and the quality of GPS device).  The end user application of this PRS feature could be supporting location based services which can be navigation (direction to hotel etc.), emergency call etc.   Process of finding UE location using PRS: The overall process of finding UE locations are based on three major steps. Step 1. UE receive PRS from cells (Reference cell and Neighbor cells)   Step 2. Based on received PRS...

LTE UE Measurement RSRP RSSI RSRQ RSTD

In LTE or any other cellular radio network, UE report some sort of signal to base station for various decision making. It could be used for better downlink scheduling (using CSI), uplink scheduling (using SRS), cell selection , handover, cell reselection , calculation of uplink and downlink path loss for power control, multipath propagation, Uplink interference  and for location based services.  All of these achieved by parameter called RSRP, RSSI, RSRQ and RSTD. RSRP: RSRP Reference Signal Received Power is the average power received by UE from a single cell specific reference signal resource element spread over the full bandwidth. It is calculated by UE for cell selection, handover, cell reselection and for path loss calculation for power control. The power measurement is the energy of the OFDMA symbol excluding the energy of the cyclic prefix.  The measurement of RSRP may be based on energy of reference signal transmitted by antenna port 1 or 1 a...

Downlink Assignment Index (DAI)

DAI ( Downlink Assignment Index ) is an index, which is communicated to UE by eNB to prevent ACK/NACK reporting errors due to HARQ ACK/NAK bundling procedure performed by the UE. To understand how DAI works we need to learn how ACK/NAK reporting used to happen in LTE TDD. In LTE TDD, UE can send single ACK/NAK of multiple PDSCH sub frame in one bit for each code word CW0 and CW1. UE perform AND logical operation on each code word CW0 and CW1 (CRC Passed/Failed) of each PDSCH received and report the result in two bits (00, 01, 10, 11) on specific uplink subframe. Below is the table which shows that which all PDSCH subframes need to be bundled for reporting ACK/NAK on which Uplink subframe for each TDD UL DL configurations (Mentioned only for config 1 and config 2 in green color). For Example:            UL/DL Configuration 1: We can see that the k value for 2 nd subframe (Uplink) are 7,6 (according to Table 10.1.3.1-1 of s...

KMIMO LTE

KMIMO is a parameter which is being used in bit collection , selection and transmission of downlink data (specifically to calculate size of a partition which is used for storing a transport block). It  is equal to  2, if UE is configured to receive PDSCH transmissions based on transmission mode 3, 4 or 8, as defined in section 7.1 of 3GPP 36.213, 1 otherwise.Also in other words , it represents maximum number of transport blocks that may be transmitted to the UE in a single TTI (Transmission Time Interval or 1ms or 1 subframe time). Questions are welcome.

CQI/PMI and RI on same subframe, SRS and PUCCH format 1/1a/1b 2/2a/2b on same subframe, SR and CQI/PMI on same subframe

If SRS and PUCCH format 2/2a/2b messages coincide in same subframe, UE shall not transmit SRS. If SRS and PUCCH format 1/1a/1b (ACK/NACK and/or +SR) coincide in same subframe, UE shall transmit SRS iff simultaneousSRSACKNACK is true.   If SRS and PUSCH RARG (Random Access Response Grant) coincide in same subframe SRS will be dropped. If SRS and retransmission of same transport block (as a part of contention based Random access procedure),  coincide in the same subframe SRS will be dropped. If SR and CQI/PMI/RI coincide in same sub-frame, CQI/PMI/RI will be dropped only if UE send SR (which is triggered by BSR) otherwise CQI/PMI/RI will be reported by UE on the same subframe. If CQI/PMI and RI is configured on same subframe and coincide, MAC will schedule RI on that subframe     and hence UE will report RI on that subframe instead of CQI/PMI (One possible reason could be Periodicity of RI is always greater than equal to CQI/PMI. Which means eNB wi...