Mobile networks provide wireless (cellular) connectivity to mobile phone users for voice calls and data transmission. Cellular networks transmit low-powered radio signals between phones and base stations, connecting those signals across the entire network. If you’re curious to learn how this works, read on for a general overview of cell systems.
Coverage
Mobile networks consist of cell towers that provide devices with wireless access. This connection is essential to phone calls, text messages, and data transmission; if you are experiencing difficulty getting strong signals, changing carriers or investing in a cellular signal booster may be beneficial.
Many Norway residents currently rely on cell phones as a mode of communication, meaning nearly everyone must compete for space on cell towers if they hope to gain a strong signal. Therefore, you must be informed about how much coverage your current carrier has in your living and work environments. Many carriers provide coverage maps online, which show where you’ll get optimal service.
Cell towers are vertical structures that use antennas high up in the air to transmit radio signals between phones and other devices and therefore cover a wider area than if placed at ground level. These antennas determine the radio frequency on which mobile phones communicate; different frequencies provide better or poorer coverage.
Higher frequencies work best for urban coverage, while lower frequencies work better in rural settings. A higher frequency also offers greater capacity, making it useful for large buildings or picocells covering only one floor.
As this can make a dramatic impactful on the performance of your phone, especially when downloading files or streaming videos, it is vital that you check coverage before signing on with any new carrier.
Most carriers provide coverage maps to show exactly how many square miles a carrier covers and where its strength lies, making it easier to identify whether your area is serviced by one carrier. These maps can help see whether your current provider covers you adequately or whether they have another plan you could switch to instead.
Paging
Paging is a memory management technique employed in operating systems to migrate processes from secondary storage into main memory, with its primary objective being to split each process into individual pages or frames and optimize usage while preventing external fragmentation.
A page is a block of physical memory with identical dimensions to its respective frame in secondary storage. A uniform page size ensures the system can quickly recognize which frame contains it for reading purposes.
This can be achieved by mapping frame numbers to logical addresses created by the CPU in secondary memory, then translating this logical address into physical addresses using the page table (address translation or translation look-aside buffer or ‘TLB’).
To determine which frame to read from, a process’s page table first verifies if the logical address it’s trying to access is valid; otherwise, it requests the OS to swap out the current frame and replace it with a new one.
As soon as a page is swapped in, its frame number changes accordingly, and an invalid bit is set, indicating this reference is actually for pages rather than frames.
Once a page is in place, a process begins reading and processing data. As it does so, the process updates its page table with the frame number and new invalid bit. When complete, the process returns to the main memory.
OSs use various paging algorithms to select page frames to swap in, each essential in optimizing efficiency. They could be based on working sets or least recently used (LRU) algorithms; either way, they predict which pages may soon become necessary and load them preemptively into RAM before any program uses them – known as pure demand paging, increasing responsiveness.
Data Transmission
Data transmission within mobile networks refers to transferring digital and analog information between devices via point-to-point or multipoint networks, usually employing radio channels as transmission media.
CDMA allows multiple handsets to share one radio channel while remaining discrete using pseudo-noise codes specific to each device, enabling phones to move seamlessly from cell to cell without breaking off communication.
Soft handover, or “soft transfer,” is an integral component of CDMA cellular technology. To avoid dropping calls from cell to cell, phones will seek out new channels as they transition.
Once a channel has been identified, the phone will notify its network that it has found one and move calls onto that new channel; this process may take several seconds.
There are various data transmission modes, each dependent on the direction, number of bits transmitted, and synchronization between transmitter and receiver. These include simplex, duplex, and half-duplex modes. The simplex mode of data transmission is one of the least used types. Here, data flows only in one direction at any given time.
Parallel, asynchronous, and isochronous data transmission is also popular methods. Each mode varies in its speed and efficiency depending on factors like data bits transmitted, device synchronization, or timing delays.
Asynchronous mode speeds up data transmission significantly faster by eliminating gaps between bits. This feature is particularly effective at sending large amounts of data quickly.
Isochronous mode is similar to asynchronous, except that data bits are sent continuously across devices synchronized in time with each other. This makes isochronous mode ideal for broadcasting video or audio signals at a constant rate.
Handover
Handover is when an ongoing call or data connection between users is transferred from one base station to another using new connection generation, signaling and routing operations, and data-flow control mechanisms to ensure a smooth transition.
Soft handover in cellular networks enables users to maintain calls or data connections while moving between cells, unlike hard handovers, which connect and disconnect at once from each base station, soft handovers are carried out simultaneously and cause less network disruption and interruption for mobile services.
Many algorithms have been proposed for handovers, including inter-frequency, intra-frequency, and combinations thereof. Some are implemented through computer tools, while others rely on field measurements or computer predictions.
Inter Frequency handovers involve receiving two user signals from adjacent sectors it serves through multipath propagation. These are important functions of mobilnett (mobile networks). The base station determines which to transmit based on each signal’s SNR value. Such algorithms tend to be complex and slow.
On the other hand, inter-frequency handovers require more complex reconfiguration of radio resources on both sides of a handover to avoid radio interference and packet loss.
Inter-frequency handovers tend to be slower and more costly than intra-frequency ones; however, with network-controlled and mobile-assisted handovers, it is possible to improve the performance of inter-frequency handovers.
As part of an inter-frequency handover, the user equipment (UE) sends information regarding its radio resource configuration directly to its target base station before initiating its first call. This enables the network to prepare it by altering both sides’ radio resources for the handover.
To enhance inter-frequency handover performance, this paper proposes a heterogeneous scheme that utilizes WiFi and cellular paths to transfer traffic. The approach helps protect a user’s data quota by offloading LTE cellular network paths during downloads.
