LTE Layer 2 user plane protocol stack in detail LTE user Layer 2 Protocol stack-the plan is composed of three substrates, as shown in the figure. Packet layer packet data convergence Protocol (PDCP) : this layer processes messages resource control (RRC) in the control plan and packages of Internet Protocol (IP) addresses in the user’s … Read more
Affects of the Channel in LTE MIMO To understand the impact of the channel, let’s assume that the base station receiver is facing many challenges in the same MIMO receiver that universal areas, but also must receive data simultaneously from multiple users. In terms of MIMO UM, each signal is derived from a separate UE, … Read more
What is the difference between 4G and 4G LTE? Many people use the terms 4g and 4g interchangeably, but they are not the same. Lets find out the difference…. Features of 4g 4G is the next step above and a 3g replacement, offering faster speeds for users who stream media (such as videos or mp3s), … Read more
GSM Underlaid Overlaid Frequency Allocation and Configuration Underlaid Overlaid Frequency Allocation In the Overlaid/Underlaid technology, all frequency carriers in the cell are divided into two parts, of which the TRX power of some frequency carriers is lowered, then two Overlaid/Underlaid with different coverage appear, as shown in the below figure. The frequency carriers used by … Read more
FDM in LTE Conventional multi-carrier operation as it is used for FDM works simply by selecting a number of center frequencies – one for each carrier to be used. The center frequencies must be spaced. In fact there is a trade-off between minimizing interference between different carriers and using the total bandwidth efficiently. In other … Read more
The price for the optimum subcarrier spacing is the sensitivity of OFDM to frequency errors. If the receiver’s frequency is some fractions of the subcarrier spacing (subcarrier bandwidth) then we encounter not only interference between adjacent carriers, but in principle between all carriers. This is known as Inter-Carrier Interference (ICI) and sometimes also referred to … Read more
Dsss – Direct sequence spread spectrum DSSS – Direct Sequence Spread Spectrum is a spread spectrum technology in which original data is expand using PN code randomly to reduce noise and this also provide high security to data as is scrambled data. Spread spectrum technology spread spectrum technology used in CDMA and Cdma is a … Read more
BCCH(Broadcast Control Channels) Downlink Only. Broadcast information of the serving cell (System Information). Transmitted on timeslot zero of BCCH carrier. Read only by idle mobile at least once every 30 secs. SCH (Synchronization Channels) Downlink Only Carries information for frame synchronization. Contains frame number and BSIC (Base Station Identity Code). FCCH (Frequency Correction Channels) Downlink … Read more
Support two basic modes: FDD and TDD modes High chip rate (3.84 Mcps) and data rates (up to 2 Mbps) Employs coherent detection on uplink and downlink based on the use of pilot symbols Inter-cell asynchronous operation Fast adaptive power control in the downlink based on SIR Provision of multirate services Packet data Seamless inter-frequency … Read more
Logical Channel = information container Defined by is transferred. Transport Channel = characteristics of transmission Described by and with data is transmitted over the radio interface . Physical Channel = specification of the information global content providing the real transmission resource, maybe a frequency ,a specific set of codes and phase. In terms of protocol … Read more