CDMA Handoff Defination,Types and Capacity Handoffs The TIA/EIA Interim Standard, Mobile Station – Base Station Compatibility Standard of Dual- Mode Wideband Spread Spectrum Cellular System (TIA/EIA/IS-95), states that a CDMA base station shall support three types of handoff processes. Which type of handoff used in cdma? CDMA to CDMA Hard Handoff A CDMA to CDMA … Read more
The design of a PN offset plan for CDMA is comparable to that of a signalling channel frequency plan in analog. The consequences of poor offset planning include the following: Active Set Pilot Interference – This phenomenon would occur in the active area and involve the active search window (SRCH_WIN_A). The interfering signal would need … Read more
In determining RF coverage in CDMA systems, the effect of interference generated from the serving cell as well as the neighboring cells must be considered, this is in contrast to the RF coverage analysis for AMPS cells where interference mainly affects the frequency assignment but not the coverage. The interference margin is dependent upon the … Read more
Soft handoff is the term that is normally associated with the fact that a CDMA system makes a connection to a target cell prior to releasing (breaking) from the source site, commonly referred to as “make-before-break”. A hard handoff, associated with AMPS, GSM, or USDC, requires that the signal strength from the target cell be … Read more
Eb/No corresponds to energy per bit over interference plus noise density for a given target FER (typical FER target is 1%). In digital communications, it is customary to designate one-sided noise density with No. In CDMA, interference is dominated by the noise generated due to other users in the system. Here No, is refers to … 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
This graphically demonstrates why interleaving data improves error correction performance of data transmission systems. In the top Image, data is sequentially read out of a buffer than goes by rows. No interleaving is employed. The data is read and transmitted in numerical order. During transmission, data blocks 5 through 8 are corrupted by some interference. … Read more
CDMA takes advantage of quiet times during speech to raise capacity. A variable rate vocoder is used; for the original vocoder the channel is a 9,600 bps when the user is talking. When the user pauses, or is listening, the data rate drops to only 1,200 bps (CDMA Variable Rate Speech Coder). Data rates of … 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