Cellular vs. Ad Hoc Networks: A Detailed Comparison

This article compares cellular networks and ad hoc networks, highlighting the key differences between these two types of wireless communication systems. We’ll explore the characteristics of infrastructure-based (cellular) and infrastructure-less (ad hoc) networks.

Understanding Wireless Network Types

There are three primary types of wireless networks:

• Infrastructure Networks: These networks rely on a fixed infrastructure, like cellular networks.
• Hybrid Networks: Combine elements of both infrastructure and ad hoc networks.
• Ad Hoc Networks: Self-organizing networks that don’t require a central infrastructure.

Let’s dive into a comparison of infrastructure-based and infrastructure-less network types.

Cellular Networks: The Infrastructure Approach

Cellular networks, such as GSM, CDMA, and LTE, represent the infrastructure-based approach.

Cellular Network Infrastructure

A cellular network comprises a central entity known as a base station (BTS) and mobile devices referred to as Mobile Subscribers (MSs). When MS-B needs to communicate with MS-C, the communication transits through the base station (BTS).

Prior to the development of cellular networks, communication relied on high-power transmitters covering vast ranges (in kilometers). However, this came at the expense of significant power consumption. Cellular networks evolved to utilize numerous low-power transmitters, each serving a smaller “cell” within its coverage area. This approach allows for supporting a larger number of subscribers.

The primary goal of cellular networks is to maximize subscriber capacity. The geographical area is divided into smaller cells, each managed by a base station (e.g., BTS in GSM). These base stations are interconnected using various topology configurations and connect to MSCs (Mobile Switching Centers) and other cellular infrastructure components.

There are two main cell types:

• Macrocells: Cover larger areas, typically ranging from 1 to 20 kilometers.
• Microcells: Cover smaller areas, typically ranging from 0.1 to 1 kilometer.

Macrocells use high-power transmitters, while microcells utilize low-power transmitters.

Access techniques like TDMA, FDMA, and CDMA are employed to enhance subscriber capacity within a cellular network. This is generally considered a single-hop system. For more information, refer to a cellular communication tutorial.

Ad Hoc Networks: The Infrastructure-less Alternative

Ad hoc networks operate independently, without the need for a fixed infrastructure.

Ad Hoc Network Example

These networks are self-organizing, utilizing a multi-hop radio relay concept. Due to the absence of a central entity like a base station, routing and resource management (e.g., frequency allocation) are more complex compared to cellular networks.

The cell boundary shown in the figure is merely representative and doesn’t have the same significance as in cellular networks.

In ad hoc networks, communication between two nodes (e.g., MS-A and MS-C) may occur through intermediate nodes (e.g., MS-D). Examples of ad hoc networks include mesh networks and WSN (Wireless Sensor Network) networks.

Nodes in ad hoc networks are more complex, requiring functionalities for transmission, reception, and routing. For more insights, refer to the WLAN Adhoc vs Infrastructure mode comparison.

Cellular Network vs. Ad Hoc Network: A Side-by-Side Comparison

The following table summarizes the key differences between cellular and ad hoc networks based on various system parameters.