Infi-Zeal's Blog

RLP The Radio Link Protocol (RLP) is used to transmit data over the GSM PLMN. RLP  covers the functionality of Layer 2 of the ISO OSI Reference Model. It  has been tailored to the needs of digital radio transmissions and provides  an OSI data link service. It also spans from the MS (Mobile Station) to the  interworking function, which is located at the nearest MSC (Mobile  Switching Center) or even further. There are currently three versions of RLP: Version 0 is a Single-link basic version, Version 1 is a Single-Link extended version, And Version 2 is a Multi-link version. RLP frames are fixed in length. The frame can either be 240 or 576 bits.  The frame consists of a header, information field, and an FCS field. The format of the 240-bit frame is:   _____________________________________   | Header  |  Information    | FCS    |   |---------|-----------------|--------|   | 16 bit ...

Here is the second post of the series GPRS guide. The LLC (Logical Link Controller) defines the logical link control later protocol to be used for (packet) data transfer between the MS (Mobile Station) and a serving GPRS support node (SGSN). LLC goes from the MS to the SGSN and is intended to be used for both acknowledged and unacknowledged data transfers. LLC's defined frame formats are based on the ones defined for LAPD and RLP.Although, there are major differences between other protocols and LLC, in particular to frame delimitation methods and transparency mechanisms. These differences are necessary for independence from the radio path. Two methods of operation are supported by LLC. These are: - Unacknowledged peer-to-peer operation - Acknowledged peer-to-peer operation All LLC layer peer-to-peer exchanges are in frames of the following format:                    1 byte    ...

GPRS Guide GPRS (short for General Packet Radio Service) is a data service upgrade for GSM networks. This allows GSM Networks to be completely compatible with the Internet. GPRS uses a packet-mode technique to transfer traffic in bursts. These bursts allow higher efficiency, and therefore higher speeds. The packet bursting technique is also used in DSL modems, and other methods of high-speed internet access. Due to this technique GPRS allows bit rates of 9.6 Kbps to anywhere more than 150 Kbps per user. There are a couple major benefits of using GPRS. These include better use of  radio/network resources and a completely transparent support of IP. Radio resources are only used when data is being sent and/or received. GPRS also provides an immediate connection (again like DSL or Cable) and a high throughput. It also allows end user applications to only occupy the network when data is being transferred, and is an almost perfect design for the short data burst which data appl...