Integrated Sensing and Communication (ISAC) 

Integrated Sensing and Communication (ISAC) comprises the technologies that integrate sensing and communication systems to efficiently use the wireless resources, achieve environment sensing over wide area and may also be for achieving the win-win situation. In recent years, ISAC has been acknowledged as one of the major components of the future sixth-generation (6G) wireless networks, especially for new applications and new scenes with high requirement of sensing and communication performance. That means that, with ISAC technique, both sensing and communication functions can be incorporated within a single hardware platform or even share the same waveform which will lead to the implementation of the lower cost of hardware along with the effective use of spectrum. It is believed that ISAC is endowed with a basic sensing capacity, which enables it to provide accurate sensing services in different scenarios, applications such as intelligent transportation, smart home Wi-Fi sensing, V2X, indoor positioning, and so on. For example, in V2X networks, the real-time information exchange with the Edge computing system is carried out by highly-performing autonomous vehicles that also have sensing capabilities to avoid risks of accidents under unfavorable weather ISAC is also designed for wearable devices which are also capable of measuring some physical signs and are capable of communicating with other wearable devices. Through the establishment of ISAC, it will be possible not only to achieve communication services but also to detect the surrounding environment; As a result, there is an expectation that it will serve as a multi-functional network to shift the paradigm in the 6G period.

Key Technologies Enabling ISAC

There are several advanced technologies upon which the successful implementation of ISAC relies because of their roles in integrating sensing and communication systems. These technologies is useful in countering challenges of ISAC such as sharing of the spectrum, interference and real time analysis. The ISAC waveform designs categorizes the waveform designs into three areas, for instance, communication-oriented waveform design (CCWD), sensing-oriented waveform design (SCWD), and joint waveform optimization and design (JWOD). Below is a detailed look at the primary technologies that will help execute the idea behind ISAC:

1. Joint Waveform Design:

a. Waveform Design

The specific design of waveforms providing both the sensing and communication functions is the core of the ISAC. Integrated waveform techniques are designed for data carrying for transmission and reception purposes with high resolution sensing. The difficulty is then to optimize these two functions in a way that will allow, for example, enough bandwidth to be used for communication and at the same time achieve high levels of sensing precision.

For instance, a waveform which can be narrowbanded for sensing can boast a high range resolution but this would adversely affect the data rate for communication. On the other hand, a wideband waveform can transmit at higher data rates at the same time the sensing accuracy is reduced.

2. Orthogonal Frequency-Division Multiplexing (OFDM):

OFDM is a kind of modulation technique that is employed in most of present day communication systems such as 4G and 5G systems. In ISAC, since OFDM can partition the bandwidth into multiple numbers of sub-carrier, both communication and sensing can be allowed.
Some of the sub-carriers in an ISAC system can be used for transmission while the others are employed in sensing. Otherwise, the same sub-carriers can be used, and because of the differences in waveforms for communication and sensing, a receiver can demodulate both signals.

3. Chirp Spread Spectrum (CSS):
CSS is a modulation technique that employs chirp sources that are long range and significantly accurate in ranging (sensing). These are important for ISAC since, similar to the case in MIMO systems, the same signal is to be used for sensing as well as communication, and CSS offers protection against interference and multipath effects. It is specially useful in such applications as when high reliability and accurate converted data is required such as in radar systems.

b. Beamforming and MIMO (Multiple Input Multiple Output)

1. Beamforming Techniques:

Beamforming is a technique that focuses a wireless signal towards a specific direction, improving both the signal strength and the resolution of the sensed data.

In an ISAC system, beamforming can be used to direct the sensing beams towards specific targets (e.g., an object or a vehicle) while also ensuring that communication beams are optimally directed towards users or base stations. This dual use of beamforming enhances the efficiency of both sensing and communication functions.

2. Multi-Beam Beamforming:

Multi-beam beamforming allows an ISAC system to form multiple beams simultaneously, each serving a different function or target.

For example, one beam could be used for high-precision sensing of a nearby object, while another beam simultaneously communicates with a remote device. This capability is especially important in applications like autonomous vehicles, where the system needs to sense the environment and communicate with other vehicles or infrastructure at the same time.

3. MIMO (Multiple Input Multiple Output) Systems:

MIMO technology uses multiple antennas at both the transmitter and receiver to improve communication performance by increasing data throughput and reliability. In the context of ISAC, MIMO can also enhance sensing accuracy.

In ISAC, MIMO can be leveraged to perform spatial multiplexing, where different spatial channels are used for different functions. For instance, some channels might be dedicated to communication, while others are used for sensing. Additionally, MIMO can improve the resolution of sensing data by using multiple antenna elements to form high-resolution spatial images.

Challenges in ISAC Systems

1. Spectrum Sharing and Interference Management:

In ISAC systems, the same frequency band could be employed for the sensing and for the communication. Interference issue between these two functions is one of the major daunting tasks that requires interference management and dynamic spectrum management so as to optimize system performance.

• Waveform Design Trade-offs:

To design waveforms for ISAC systems, there are always different and sometimes opposing objectives such as achieving a high data rate for communication and high accuracy for sensing and detection. One of the major challenges for the automaker is to strike a right form of interfacial design that can satisfy both functions without compromising the performance of the other.

• Resource Allocation:

There is an optimal sharing of a scarce resource which includes power and or bandwidth between sensing and communication. The changes in the requirements of both functions in organizations’ operations require real-time changes in resource allocation.

• Latency and Real-Time Processing:

ISAC systems have to have very low latency, especially with applications such as autonomous vehicles. Ideal and efficient data processing and coordination of the sensing and communication tasks are fundamental to the achievement of the system’s goals.

• Complexity in System Design:

Sensing and communication together make the system compact and complicated. The most complex design thrust can be argued to involve designing ISAC systems that are capable of performing two major tasks, with the aid of well-developed algorithms and hardware.

• Standardization and Compatibility:

It has been seen that there are no specific guidelines or SOPs for ISAC systems which forms a problem. For most of the proposed technologies to be effectively integrated in the ISAC framework they must complement the current communication and sensing technologies.

• Deployment and Scalability:

To spread ISAC systems for deployment in settings like large and small cities, meta-areas, or rural areas there are challenges. More so, it will be of essence to guarantee that the ISAC solutions client-satisfaction levels are enhanced, inexpensive, and flexible to be applicable to numerous environments.

Patents in Integration of sensing with communication in ISAC

Huawei Technologies Co Ltd – Communication and Sensing in Half-Duplex Wireless Networks

While most classical wireless communication networks are not well equipped for integration of sensing mechanisms, especially the networks that operate in half-duplex, are challenging. One challenge is that the same physical resources cannot be used for both transmission and reception of signals, creating inefficiencies in the sensing and communication processes—they are particularly undesirable in today’s monostatic radar-based networks.

Generally, the patent (US11474197B2) provides a mechanism in which a device switches between an active mode and a sleep mode while in a sensing period. During the active phase, it broadcasts a radio frequency (RF) pulse signal, which also serves as a modulated RF carrier signal. Passive phase receives the reflection of the RF pulse to sense the environment and it also receives the communication signals. The design chooses waveform and its duty cycle to maximize the sensing performance while minimizing the required number of communication resources in half-duplex networks for sensing/communication integration.

Qualcomm Inc – Sounding Reference Signal Waveform Design for Wireless Communications


In the wireless communication systems, especially those utilizing the share spectrum, the management of the resources such as time and frequency is always a problem; this is due to the fact that when the number of UEs which wants to transmit SRS is large, then it will cause a lot of problems. Traditional techniques entail using multitudes of LBT gaps for each transmission, thus minimizing the network efficiency and channeling capacity and using up channels in disintegrated manner.

According to the patent (US11777764B2) it is aimed to generate a method to synchronize SRS in frequency on a number of OFDM symbols so as to enable multiple UEs to employ a single LBT gap to initiate the transmission of SRS. This is made possible through the frequency domain staggering and Orthogonal Cover Codes (OCC) for the possibility of SRS simultaneous transmission. Use of these techniques increases the overall system capacity by decreasing the number of LBT gaps needed and Spectrum Bandwidth i.e. optimally utilizing the Spectrum Resources in turn which indirectly benefits Integrated Sensing and Communication (ISAC) by optimizing wave form designs and spectra management.

Samsung Electronics Co Ltd – Method and Apparatus for Supporting Multiple Reference Signals in OFDMA Communication Systems Top of Form

As the number of transmission antennas in wireless communication systems increases to improve data rates and system throughput, there is a significant challenge in managing the overhead associated with transmitting Reference Signals (RS). The need arises to support multiple antennas while minimizing the impact on legacy User Equipments (UEs) that can only handle a smaller number of antennas.

This patent (USRE47485E1) proposes a method for transmitting RS from multiple antennas using a combination of frequency division multiplexing (FDM), time division multiplexing (TDM), and code division multiplexing (CDM). The method allows for efficient RS transmission by placing new RSs in the data transmission region, outside the control signal region, and periodically transmitting RSs for channel quality estimation. This approach reduces overhead, maintains backward compatibility with legacy UEs, and supports enhanced MIMO and beamforming capabilities in modern wireless communication systems.