Cell Edge Rate in LTE is simple if it’s High then Coverage Low and if It’s Low then Coverage high similar to Frequency selection. Not clear lets understand in detail. Cell Edge Rate in LTE Similar to other wireless communications systems, such as CDMA2000 EVDO, WiMAX and HSPA, the LTE features a rate layering feature. … Read more
The third assumption—that the background noise is Gaussian and uncorrelated with the transmissions—is especially suspect in a cellular MIMO system. All well-designed cellular systems are by nature interference limited: If they were not, it would be possible to increase the spectral efficiency by lowering the frequency reuse or increasing the average loading per cell. In the … Read more
CDMA forward channel carrier power varies greatly depending on how many traffic channels are in use, the characteristics of the users voices, the Forward Power Control settings as requested by each subscriber unit in use, and the power allocated for overhead functions (Pilot, Page and Sync). An approximation of the CDMA forward channel carrier power … Read more
Closed loop power control is used to allow the power from the mobile unit to deviate from the nominal as set by open loop control. This is done with a form of delta modulator. The base station monitors the power received from each mobile station in reverse link and commands the mobile to either raise … Read more
The Open Loop Power Control require in cdma due to following reason. Assumes Loss is Similar on Forward paths and Reverse Paths Receive Power + Transmit Power = -73 All Powers in dBm Example: For a Received Power of -85 dBm Transmit Power = (-73) – (- 85) Transmit Power = +12 dBm Provides an … Read more
Power Control Required in Reverse link cdma due to following reason. Maximum System Capacity is Achieved if: All Mobiles are Power Controlled to the Minimum Power for Acceptable Signal Quality in Reverse Link. As a Result, all Mobiles are Received at About Equal Power at the Base Station Independent of Their Location in reverse Link. … Read more
WDMA Air interface or Uu Interface contains 3 layers which describe as follow, The WCDMA layer 1 supports all functions required for the transmission of bit streams on the physical medium. It is also in charge of measurements function consisting in indicating to higher layers, for example, WCDMA Frame Error Rate (FER), WCDMA Signal to … Read more
The TX diversity methods in the open-loop mode are as below Space time-block coding-based transmit-antenna diversity (STTD) Time-switched transmit diversity (TSTD). In UMTS STTD the data to be transmitted is divided between two UMTS transmission antennas at the base station site and transmitted simultaneously. The UMTS channel-coded data is processed in blocks of four bits. … Read more
Each 20 millisecond frame in EIA/TIA-95-B CDMA is divided into sixteen “power control groups”. When the mobile transmits, each power control group contains 1536 data symbols (chips) at a rate of 1.2288 Mbps. When the voice coder moves to a lower date rate, the CDMA mobile bursts its output by only sending the appropriate number … Read more
Voice data at 9600 bps or 14400 bps (full rate) is first passed through a convolutional encoder, which doubles the data rate for the 9600 bps case or increases it by 1.33 times for the 14400 bps case. It is then interleaved, a process that has no effect on the rate, but does introduce time … Read more